This Week's Horticulture News/Information

Snails and Slugs

Snails and slugs are noted for their voracious appetites, eating holes in the leaves of hosta (their preferred food) but also munching on roses, ferns, impatiens, begonias, and fruits, including strawberries and tomatoes. You may not see the actual snails and slugs themselves since they prefer to feed at night or on cloudy days, but if you see holes AND their silvery slime trails, these guys are making themselves at home. Typically, snails and slugs prefer to slime their way to the center of leaves where they will eat holes between leaf veins. Sometimes they eat their way inward from leaf edges.

Both snails and slugs are mollusks. They move about, crawling along with one muscular “foot” structure. This muscle secretes mucus to make travelling easier.  Snails and slugs have a similar appearance except snails have a shell and slugs are shell-less.

Gardeners should employ a multitude of strategies to lower snail and slug numbers.

•Surround plants with diatomaceous earth in a band about one inch high by three inches wide. Diatomaceous earth is tiny shell shards of ancient marine animals.  As slugs and snails crawl across diatomaceous earth, their bodies are punctured, causing dehydration and death. Diatomaceous earth loses its effectiveness when wet, so re-applications will have to be made after a rainstorm.

•Use drip irrigation to reduce humidity and wet surfaces. Dry areas incur less snail and slug activity than damp places do.

•Snails and slugs are attracted to the smell of fermentation. You can lay a beer trap for them by burying a shallow dish in the soil, so the top of the dish is even with the soil surface. Fill the trap with beer or near beer. Snails and slugs will crawl towards the scent, fall into the trap, and then drown. Check the trap regularly, emptying it and adding more beer as needed.

•Lay old boards around the base of plants. Snails and slugs like to congregate in cool moist places. Every morning, the boards can be flipped over, and gardeners can step on the mollusks hiding there.

•Iron phosphate, sold as Sluggo® or Escar-Go®, interferes with snail and slug metabolism, causing them to cease their feeding and later dying. These products are labeled for use on ornamentals and food crops.

•Pesticides containing the active ingredient metaldehyde are effective against these mollusks by dehydrating them but may be ineffective when rainfall or irrigation provides the necessary water to re-hydrates snails and slugs.

Fall Armyworm

The fall armyworm, Spodoptera frugiperda, is a pest of row crops and lawns, preferring Kentucky bluegrass above other types of lawn grasses grown in the region. The caterpillars eat the blades of grass, to the point of turf thinning and browning. Sixth instars, the largest they’ll grow as caterpillars, are 1-¼ inches long with 3 stripes extending along their length and an inverted “Y” shape on their head. Pupation takes place in the turf, with the adult moths emerging to mate. Sources differ on the number of eggs each female produces but it is many, ranging from 100 to 1000. Egg masses can appear on buildings, fences, plants, and outdoor furniture.  Eggs develop into first instar caterpillars in just 2-5 days.  Initially, feeding is minimal, owing to the caterpillar’s small size, but as they grow, their appetite increases and the damage they cause more readily apparent.

The FAW is a tropical pest, overwintering where winters are mild, in southern Florida and Texas, and blown to northern locations via storms and the accompanying winds in summer. The “fall” in its common name refers to caterpillars becoming prevalent in late summer and early fall and “armyworm” references the caterpillars moving across the lawn in a line, eating everything as they go.  FAW has no diapause, a suspension of development to successfully overwinter harsh winters like some of our native insects do. The FAW will be active until the first freeze at which time all feeding and activity by the FAW ends—at least until next year’s storms blow moths into our region.

Insecticides will be most effective when caterpillars are newly-hatched and damage is not noticeable. To monitor for the FAW, mix a container of soapy water and dump it on the lawn.  If the caterpillars are present, they will move above the lawn’s surface. Insecticides containing one of these active ingredients are effective against the fall armyworm:  carbaryl, chlorantraniliprole, azadirachtin, Monterey B.t., spinosad, and bifenthrin. Once the lawn is free of the FAW, overseeding may be necessary to fill in thin areas. More information about the fall armyworm may be found here: https://www.turffiles.ncsu.edu/insects/fall-armyworm-in-turf/ .

Selecting Trees

With September upon us, it’s time to think about tree planting. If tree selection is on your to do list, putting the effort and time into researching what trees to plant pays off in a tree canopy that nets long term benefits in shade, beauty, soil stabilization, and stormwater mitigation.

Start by taking an inventory of what is already there—not just what is in your yard but in the neighborhood as a whole. Being the sixth person on your block to plant the same tree in the yard means loss of significant tree cover when an insect or disease wipes them out. (Think of the emerald ash borer with ash trees.) Diversifying trees in a landscape lends resiliency and negates the need for treating every single tree when a species-specific problem strikes.

Next, seek the input from tree people. Not tree people who blog from their work site far away, but tree people from your region, who have experience in troubleshooting tree health issues and provide consultation for trees problems that have developed 5-10 years after trees are planted. Understanding what problems are commonly seen is information worth knowing when selecting a tree.

The final consideration is the mechanism for how the tree is grown out at the nursery—potted, B & B (balled and burlapped), grow bag, and bare root. Potted trees should be in a specialty pot that prevents roots from circling, which would require removal/disentangling before planting.  B & B trees deliver larger trees but also have lost a considerable portion of their root system when dug by a hydraulic tree spade. Grow bags are made of a heavy-duty mesh fabric that allows roots to breathe and develop without circling inside the bag. Bare root trees, primarily available for purchase in the spring, saves considerable costs in transport because there isn’t the added weight of soil. All of these mechanisms for roots have advantages and disadvantages.

Don’t be afraid to purchase a small tree. “What is a fast-growing tree I can plant?” is a common question and too often results in planting the same trees over and over again.  Small trees, having a more complete root system, don’t have to overcome root loss and girdling, sending energy into top growth, a huge benefit.  The old belief to stay away from planting an oak because it is slow growing is no longer true when beginning with a small tree.

Many problems are actually created when trees are planted, so pay close attention to the root flare, the part of the tree’s anatomy where the trunk flares into a root system.  If the flare isn’t visible above the soil line, the tree is too deep. Trees can be too deep within the pot, ball, or grow-bag themselves so be sure to determine where the flare is located on the tree and then plant so the flare is slightly above the soil line.

Looking for a good tree list?  Start with the Nebraska Statewide Arboretum’s “Trees for Eastern Nebraska”:   https://go.unl.edu/7iwr .

Late Season Pest Management in the Vegetable Garden

This is the season of vegetable abundance and while it would be great if our most pressing concern involved harvest, instead we find vegetable pests are an ongoing problem.

Squash Bugs

This sucking pest reduces leaves to dry crunchiness, interfering with the process of photosynthesis and vegetable production. Where their numbers are small, adult and immature squash bugs can be handpicked from cucumber, melon and squash plants and dropped into a bucket of soapy water.  When populations are high, Neem oil can be applied to the bugs and their eggs (red in color and massed in the “V” of the leaf veins on the undersides of leaves.)  Trap crops of delicata or blue hubbard squash are preferred food sources for squash bugs, minimizing their damage to other crops, so long as gardeners still manage pest numbers in the trap crops.

Squash Vine Borer

No insect causes the collapse of squash vines faster than squash vine borer. Eggs are laid at the base of stems by the adult, a clear wing moth. Hatching caterpillars bore into stems, feeding on water-conducting tissues. Since it is almost impossible to eradicate them once they are in the stems, prevention is key. Wrapping the base of stems with cardboard rolls or strips of aluminum foil will prevent access to stems by the egg-laying female moths.

Cabbage Looper Caterpillar, Diamondback Moth Caterpillar, and Imported Cabbageworm

Caterpillars in this group feed on the leaves of cole crops. Gardeners wanting to get in a second planting of cabbage or broccoli can be frustrated by these insect pests coming to the table with forks in hand.  Initial holes from feeding are gradually enlarged to leave nothing behind but a few leaf veins. Squishing caterpillars between your fingers is certainly satisfying but Dipel (B.t.), Neem oil, or Spinosad will work too.

Blister Beetles

Blister beetles have wide-ranging food preferences among crops, ornamentals, and vegetable gardens, eating holes in the leaves of eggplant and potato. This species is not all bad—blister beetle larvae feed on grasshopper eggs.  The bodies of the blister beetle contain cantharidin, which can cause blisters on skin when insects are crushed.  Their numbers are rarely high enough in vegetable gardens to warrant application of an insecticide so instead, gather blister beetles with a gloved hand and drop them into a bucket of soapy water.

National Potato Day August 19

In honor of National Potato Day, let’s pay homage to the spud.  Here are some things to know about potatoes and potato plants:

•There are blue, white, and gold-fleshed potatoes, as well as round ones, oblong ones, lumpy ones, and fingerlings. Skin colors are red, russet, blue, and golden.

•Seed potatoes should be certified disease-free to prevent transfer of diseases to new crops and contaminating the soil.  Late blight, Phytopthora infestans, will long live in infamy as the pathogen that set into motion the Irish potato famine. The fungal spores of late blight and other pathogens can persist in soil for many years, affecting the health of future potatoes planted there.

•Seed pieces (divided potato sections with at least one eye) can be planted in early spring, 3-5 inches deep. Plants will handle a light frost but not freezing temperatures and extended cold. As plants grow, soil can be mounded up around stems to provide more opportunities for tubers to develop.

•New potatoes can be harvested by carefully pulling away the soil from the potato hill, gently pulling a few potatoes, and then replacing the soil, leaving the plant intact to continue growing.

•Juglone, the naturally occurring herbicide emitted by black walnut trees, is highly toxic to potato plants and will cause wilt. Plant potatoes well away from any black walnut trees.

•Flea beetles and leafhoppers feed on potato foliage but the most voracious eater, the Colorado potato beetle, can be the toughest to manage. The CPB has developed resistance to many of the insecticides used to manage their numbers.  In a home garden, pluck beetles and their spongy offspring and drop them into a bucket of soapy water.

•Some potato varieties flower and set fruit atop plants. The green fruit is about the size of a cherry tomato and full of seeds, which do not carry pathogens like the tubers do. Indigenous people saved seeds to start plants the next year when disease problems accumulated in tubers.

•Potato scab is a flaky, crusty abrasion on the skin of the potato itself. While unattractive, it is only cosmetic, and potatoes with scab can be eaten when peeled. Scab tends to develop on potatoes growing in a soil environment with a high organic matter content.

•Potato tubers are stem tissue and capable of photosynthesis, turning green and producing an alkaloid that is toxic to humans. Keep harvested potatoes out of light and stored in a cool dry place prior to eating them.

•Potatoes and tomatoes are closely related.  Hybridizers have tried crossing these plants in the hope of getting seeds that produce both tubers and tomatoes from the same plant, but, alas, got plants that produced neither. The effort has been successful, however, by grafting a tomato top to a potato root system.

Heavy Rainfall, Strong Winds, High Humidity

Nothing deepens the appreciation for rainfall like a gentle rain and a light wind. But this is the Midwest, lest we forget, and weather conditions rarely follow our druthers. Take, for instance, the most recent rainfall and wind event. The tomato cages, with plants weighted by many tomatoes, bent to the ground in our Growing Together Nebraska garden. Luckily, the heavy winds didn’t rip up roots, but the tomato plants’ fall caused damage to the nearby pepper plants, necessitating early harvest of some of the peppers.

Vegetable Plants

Ponding water prevents oxygen reaching plant roots, where anaerobic conditions promote root and crown rot, leading to rapid plant decline.  Incorporating lots of organic matter into a clay soil will increase water infiltration, making ponding less of a problem. Water droplets splashing from the soil to the undersides of plant leaves inoculates them with pathogens like anthracnose and Septoria leaf spot on tomatoes. Mulching with shredded newspapers around vegetable plants lowers the possibility of pathogen-carrying droplets splashing onto leaves.  As water evaporates from plants and soil, humidity is increased, furthering the likelihood of fungal pathogens gaining a foothold. Plants susceptible to fungal diseases can be preventatively sprayed with a fungicide but once fungal diseases are ensconced in leaves, fungicides provide little to no curative effects.

Trees and Shrubs

The ideal time to trim trees and shrubs is April through June.  Nature’s inopportune storms are oblivious to this timeline and this will entail pruning outside the ideal time. Removing dangling branches, known as “hangers”, as well as making clean cuts to jagged stems are important for several reasons—human safety and tree health being foremost. Wound treatments are not recommended as they hasten tree decay. Fertilizing to “help” trees and shrubs following a stressful event favors many fungal and bacterial infections and is not advised.

Lawns

Rust is a fungal disease of turfgrass, becoming noticeable when a walk through the lawn results in rusty colored shoes.  Close mowing, night watering, a thick layer of thatch and low soil fertility contribute to rust development. Again, fungicides will provide little in the way of curative effects, so correcting poor management practices provides the best chance to stop the disease from developing further.

Sanitation

Since fungicide applications are limited in providing curative benefits, clean-up of fallen and broken plant debris, as well as removal of disease-damaged leaves are the best options to limit disease spread. Increasing air circulation, keeping irrigation water close to the ground, and mulching so soils retain their moisture are all important practices for good plant health.

The Cicada Killer Wasp

The size of the cicada killer wasp is alarming to many people, prompting phone calls and emails to Nebraska Extension Offices with questions of how best to eradicate them. The female, at 2 inches long and with three bright yellow stripes on her abdomen, is one of the largest insects in our landscape. The male is large too, though smaller than the female at 1-½ inches long, and is stinger-less. Both males and females are pollinators, moving pollen as they feed on flower nectar.

The cicada killer wasp gets its name from, as you would guess, killing cicadas.  The female cicada killer wasp has a stinger that she uses to inject venom into cicadas, not killing the cicadas but instead paralyzing them.  She then flies the cicada to her nesting area, dragging it underground. The nest she digs herself, locating it 12-15 inches below ground in loose dry soil. The female wasp, knowing the gender of her eggs, will see to it that male eggs each get one cicada as a food source, while the female eggs, because they develop into larger insects than their male counterparts, will get two cicadas each.  A hatching larva will bore into the paralyzed cicada, feeding on the cicada’s internal organs. Larvae will feed over a ten-day period, leaving behind empty cicada exoskeletons when finished. In readiness for winter, larvae spin a cocoon around themselves for winter protection.  Pupation and emergence as adults take place in the spring.

Female cicada killer wasps are mild mannered, often going about their business and paying little attention to human movement in the area. They will defend themselves if treated roughly so leaving them to conduct their activities unhampered is a good idea.  The male cicada killer wasp is territorial and because he is stinger-less, will scare away people and would-be predators by buzzing around them. This is all for show, however, because males cannot sting.

The dry open-soil areas beneath large shrubs or under roof eaves, around rock retaining walls, and sometimes in vegetable gardens are places where cicada killer wasps like to dig their tunnels. Tunnel openings are ½ inch across, slightly mounded, and made up of loose soil. Once the female has completed her egg-laying and cicada-provisioning, she will close the opening to the tunnel, leaving eggs to hatch and larvae to develop on their own.

Treatment to manage cicada killer wasps is often not necessary and broadcast insecticide applications in the area where they burrow are not effective. Changing the environment where wasps prefer to nest is an effective means of ensuring they re-locate—wetting down the area with water, filling empty spaces with plants, and mulching with a 2–4-inch layer of wood chips.

A common predator of cicada killer wasp larvae are the immatures of the velvet ant.  This ant is not an ant at all, but a wasp, sporting velvety rust-colored hair on its body. While colorful to look at, the velvet ant has a venomous sting that is one of the most painful of all insect stings/bites. Velvet ants should never be picked up for closer examination.  

More information about the cicada killer wasp may be found here: Cicada Killer Wasp | Nebraska Extension in Lancaster County (unl.edu) .

Colorado Potato Beetle

From its name, it would be nice if Colorado potato beetles were only found in Colorado but unfortunately, that is not the case. The CPB, Leptinotarsa decemlineata, is a serious pest of potato and related crops in North America.  Recently, the CPB was found at the Growing Together Nebraska garden here in Fremont, feeding on the foliage of both potatoes and eggplant. This insect has a voracious appetite, eating leaves down to almost nothing, which in turn decreases yields. 

Both larvae and adults feed primarily on potato leaves, but can infest other plants in the nightshade family, like eggplant, pepper, tomato, and tomatillo.  The larvae are soft-bodied, brick red to orange-red in color, and have two rows of dark spots running down each side of their bodies. Adult beetles are 3/8-inch-long ovals, striped with alternating strips of black and yellow.  Adults overwinter in the soil, emerging in the spring to mate and lay eggs.  The female can lay up to 350 yellow-orange eggs throughout her life, laying clusters of about 20 eggs at a time on favored food sources, extending egg laying over several weeks. Once eggs hatch, larvae initially cluster together, eventually dispersing to feed throughout the plant. At the larvae’s fourth instar of maturity, they drop to the ground, burrowing into the soil where they eventually become pupae. When CPB numbers are high, egg, larvae, and adult life stages will all be present. 

The easiest management technique (and least likely for beetles to develop insecticide resistance) is through hand-picking. Larvae naturally drop to the ground when potato leaves are disturbed, so place a bucket or plastic bag underneath foliage, give the plant a gentle tap, and the larvae will drop right in. Check undersides of leaves for egg masses, and then place insects and eggs in soapy water to kill them. Rotate where potato crops are planted from year to year and clean-up fallen plant debris. The CPB has developed resistance to many insecticides, including carbaryl (Sevin), permethrin, pyrethrin, and the class of insecticides known as neonicotinoids. If an insecticide is used, opt to spray when larvae are small, using products with known efficacy such as spinosad (a soil bacterium) or azadirachtin (derived from the Neem tree).

For more information on the Colorado potato beetle, follow this link: Colorado potato beetles in home gardens | UMN Extension .

Tomato Viruses

As difficult as blights are to manage in tomatoes, viral diseases are far worse. This is because there are no effective products to stop their spread.  To make matters even more challenging, virus infection is most often the work of sap sucking insects, such as aphids, thrips, and leafhoppers, that vector diseases. Insecticides to stop these insects provide limited results, often after insect feeding has already enabled virus spread to plants.

Viral diseases have a range of symptoms, each specific to the type of virus—ringspots on leaves and fruit, yellowing curled leaves, purplish leaf veins, and bright yellow irregular leaf blotches. All viruses reduce plant vigor and tomato production.

Some viral diseases, like curly top and tobacco mosaic, primarily affect tomato foliage.  With less leaves to photosynthesize, however, reduced yields should be expected.  An infection of curly top results in thickened and twisted yellow leaves while tobacco mosaic produces yellow patterned leaves on stunted plants.

Viral diseases that affect foliage and fruit include alfalfa mosaic and tomato spotted wilt. Infection of alfalfa mosaic results in patchy brown lesions and splitting of tomatoes. With tomato spotted wilt, ringspots appear on fruit and the flavor will be off-tasting.

Rogue out tomato plants that are afflicted with viruses. Infected plants are a source of inoculum that can be spread to healthy plants by insect vectors. Choose tomato varieties noted for their resistance to viral problems. For instance, the designation “TMV” after the tomato variety’s name indicates it is resistant to tobacco mosaic virus.  Since some virus transmission is from contact with infected plants, be sure to clean up last year’s tomato debris before planting and rotate crops to decrease disease carryover. Reflective mylar or aluminum foil placed beneath plants will repel insects, at least until plants get so large that they shade the reflective benefits of the mylar/aluminum foil.

Graft Union Incompatibility

Lots of trees can be grafted—fruit trees, shade trees, and even small ornamental trees. Grafting is the art of putting together two different parts of trees to make one new tree. Unlike Frankenstein, the results are not monstrous, but instead the new tree will have some of the best traits of each of its parts. The rootstock can impart things like dwarfness, winter hardiness, and soil pH adaptability, among other positives. The top of a graft union, called the scion, may bring bigger flowers, more fruit, and/or a different form than normally found (think of a lilac bush grafted onto a standard). If a cutting can be slow to root, grafting to a root system can get the plant off to a quicker start, making for a saleable tree sooner rather than later.

While nurserywomen and men seek out closely related rootstock-to-scion-wood unions to ensure grafting success, sometimes issues of incompatibility develop. These issues can occur right away, or they can develop 15 years after the tree has been planted in its permanent home.  Symptoms of graft union incompatibility are odd, with a range of curious developments.  The trunk may develop girth far beyond the size of the rootstock, giving the plant a bulging top-heavy appearance. Another indication of graft union incompatibility is overgrowth of roots, with roots aggressively forming, one over the top of the other, gradually encompassing and constricting the scion itself. When this occurs, reduced leafing and branch dieback in the scion are typical. The important thing to remember with graft union incompatibility is that it is a location of weakness, leading to possible breakage at the juncture.

There are a few reasons why graft unions fail.  Sometimes the rootstock and scion are not related closely enough. If the two components belong to the same plant family but not the same genus, then incompatibility can develop.  Another possibility-- disease-causing organisms--may be present when the parts are grafted, sealing in pathogens, and creating the perfect environment for their growth and development. A final possibility for graft incompatibility is the grafting technique itself. There are a number of grafting methods, each with its own benefit but not necessarily suited to all grafting endeavors.

Not all bulges at the base of grafted plants are indications of graft incompatibility. A slight swelling is normal. Roses are some of the most common grafted plants in our landscapes.  Monitoring their growth is necessary to ensure sprouts arising from the graft union or below are removed.

More about graft union incompatibility may be found here: https://extension.umd.edu/resource/graft-failure .

What Nebraska Extension Master Gardeners Are Up To

Nebraska Extension Master Gardener Volunteers are hard at work.

In Dodge and Washington Counties, Master Gardeners are working on food gardens. Growing Together Nebraska is a joint effort between Master Gardeners and Extension Nutrition Educators. Vegetables and herbs are planted, cared for, harvested, weighed, and donated to local food pantries. Donations are already underway, with the harvest of radishes and basil! A huge variety of vegetables have been planted, with tomatoes, peppers, onions, potatoes, broccoli, cucumbers, squash, zucchini, and pumpkins (to name a few) eventually providing nutritious locally-grown food for the food insecure.

In Dakota County, Master Gardeners are pruning the fruit trees at the South Sioux City Community Orchard.  Located on park property, the orchard is a cooperative effort between Nebraska Extension and the South Sioux City Parks Department. Guided by Master Gardeners, locals can volunteer their time to manage weeds, water, and prune trees, earning a portion of the fruit harvest for themselves.

In Burt County, the Tekamah Pollinator Garden is readying for visitors.  With the idea of planting gardens primarily to benefit insects, the popularity of pollinator gardens is on the rise. Groups from colleges, schools, and garden clubs tour the garden and take ideas back for their own projects.

In Thurston County, Master Gardeners from the UmoNhoN Nation Public Schools are working with youth in summer programs to learn about vegetable gardening through the Farm to School project. 

In Washington County, Master Gardeners grow historic varieties of vegetables at the Fort Atkinson State Historical Park in Fort Calhoun to demonstrate the kinds of vegetables families of soldiers and tradespeople grew. At the monthly living history demonstrations, Master Gardeners are on hand to talk about the first winter at the Fort and how a little-known native plant called ground nuts saved lives from the scourge of scurvy (a nutritional deficit of vitamin C). Vegetables from this garden are donated to the Growing Together Nebraska project.

This is just some of the many projects Master Gardeners throughout the area are involved in. Stay tuned as I share more about their activities.

Winter Dieback of Trees and Shrubs

A recent discussion thread launched on the Shady Lane listserv by Justin Evertson of the Nebraska Statewide Arboretum asked observers how trees in their landscapes weathered the negative double-digit cold of winter. Used to extreme cold conditions, native trees and shrubs weathered the tough winter best. Others (that were thought to be very cold hardy) lost all living canopy growth and are now sending out sprouts at the base. Still others are no surprise at all, such as the Japanese maple, a marginal species for this region at best, which had major dieback and/or outright death.

Overall, the winter injury is divided into 3 main groups, with the first being composed of trees and shrubs with sparsely-leafed branches and stems. Woody plants that fall into this category include privet, burning bush, lilac, tuliptree, and sycamore. For these plants, recovery is a strong possibility though it may take several years.

The second group is made up of trees and shrubs that lost their top branches and stems to winter damage, with new growth arising from the base. Trees and shrubs in this group include black gum (also known as tupelo), Korean evodia, magnolia, and Siberian elm. The good news about this group is the plants survived.  The bad news is tree growth is nothing like normal. A more accurate question would be do we really want to save them? That is a tough one to answer.  It involves years of monitoring the tree,  retraining a new central leader, and thinning out sprouts that give the appearance of a shrub instead of a tree. If you are willing to devote the time and effort to take on this task, then do so. Otherwise remove the old plant and replace it with something with greater hardiness.

Conifers suffered dieback too, with the death of the tops of trees. Spruce trees were hit hardest, but juniper and pine were also affected. The dead central leader can be pruned out and a lower branch can be trained upright by tying the branch to a pole placed along the stem.  Lower limbs can be trimmed back to give the new leader time to grow.  Staking and tying materials are to be removed in one year to forestall stem girdling. 

The third group consists of plants lost altogether, like boxwood and doublefile viburnum. Thankfully, the number of plants in this group is not many but planting something believed to be hardy only to lose it is frustrating. In many cases, trees had been growing successfully for years, only to die from freeze injury just when we thought they were large enough to weather most anything.

Oddly enough, not all species were affected uniformly. The paperbark maple in my yard looks just fine while in other landscapes, the tree had serious dieback. Tree health prior to the winter will impact its survival from an extreme weather event and the drought of 2020 compromised tree health.

This past winter emphasized the importance of provenance. Provenance refers to the source of seed, with trees grown from regional seed sources showing higher survivability than trees grown from seeds that come from outside the region. Differences in soil, precipitation, winter cold, and summer heat will negatively impact trees and shrubs grown from seed sources outside the region. When purchasing a tree or shrub, researching the plant’s hardiness and where it came from are essential to plant success.

Colorado Spruce

The Christmas tree shape of Colorado spruce is beautiful indeed, but several common problems make growing them a challenge.

Deep Cold

February’s hard hit of negative double digit cold resulted in the tops dying out of spruce trees. This caused cracks to develop in trunk tissues that then leak sap. This is apparent with the accumulation of white crust on the trunk and branches. Once cracks develop, canker pathogens like Cytospora gain access to conductive tissues within the tree, widening the wound. Unfortunately, sprays and drenches do not counter the effects of Cytospora canker. Prune out the dead central leader and re-train a lower branch to take over as the new central leader.  Branches below the new central leader can be cut back to restore the pyramid shape. How To Prune Coniferous Evergreen Trees (uidaho.edu)

Spruce Spider Mite

The spruce spider mite is a small sucking pest of spruce and other evergreens. With their needle-like mouthpart, the spruce spider mite removes sugars, sap, and chlorophyll from foliage. When mite populations are high, needles present an off-color appearance of dusty green. Leaves eventually turn brown altogether and fall from the tree. The spruce spider mite is active in the cooler parts of the season, with activity peaking in spring and fall. A hand lens or a microscope is a handy tool to identify spruce spider mites, but the paper test can also be applied. Using a sheet of white paper, tap a branch over the paper and look for small dots moving across the page. Miticides are effectively applied when mites are active in spring and fall. Rainfall has a nice way of keeping mite populations down by drowning them. Ins of ev 3-6-09 (unl.edu)

Bagworm

Tear drop-shaped bags and loss of needles are clear indications of bagworm infestations. A few caterpillars can defoliate trees in a relatively short time frame, leaving branches bare and killing next year’s growth buds. Products containing the active ingredient Bacillus thuringiensis (Bt) can be applied in mid-June to early July to target these caterpillars when they are small. As the caterpillars grow, so do their appetites, causing significant defoliation and being difficult to manage as well.  Come August, caterpillars are too big to manage with insecticides and hand-picking bags from trees is really the only option. Be On the Lookout for Bagworms | Nebraska Extension: Community Environment | Nebraska (unl.edu)

Rhizosphaera Needle Cast

This fungal disease, caused by the pathogen Rhizosphaera kalkhoffii, interferes with intake of carbon dioxide through the needles. The needle’s breathing structures, known as stomates, are clogged with the fungus’s spore producing structures. Without the ability to breathe in carbon dioxide and exhale oxygen, trees are unable to photosynthesize, starting a cycle of decline that, if left untreated, can cause defoliation and death to the tree. Cool wet springs provide the perfect conditions for development of needle cast. A hand lens or microscope is handy for spotting infected stomates, which appear as rows of black dots on needles. Good air circulation, keeping irrigation water from wetting foliage, mulching beneath trees, and application of a fungicide will manage needle cast.  Dis of ev 1-20-09 (unl.edu)

Tree Overuse

Colorado spruce is suited to rocky, well-drained soils, in locations that receive 6 or more hours of direct, uninterrupted sunlight daily. Heavily irrigated clay soils and shady sites are situational conditions ripe with opportunity for decline, necessitating costly interventions that may or may not work.

With the tree popular for use as accents in front yards, as windbreaks, and in allées, the Colorado spruce has become the dominant evergreen in the landscape. As with any over-used plant, a major concern is the potential for an emerging insect or disease problem to infest the species (think: emerald ash borer for ash, Dutch elm disease for elm, and pine wilt for pine.) Diversity is always the best choice, especially when utilizing trees with insect and disease resistance. Substitutions for this much-overused tree include juniper, Concolor fir, Douglas fir, Fraser fir, Norway spruce, Black Hills spruce, and Ponderosa pine. 

Winter Damage and Herbicide Drift

Winter Damage

February’s deep cold separated the marginally hardy plants from those that weathered the winter without problems. The lower portions of stems of some trees and shrubs, protected by the snow, flowered as usual and are sending out new leaves. Unfortunately, the portions of plants not protected by snow remain lifeless or are slow to leaf out. Burning bush, Japanese maple, doublefile viburnum, forsythia, black gum, Korean Evodia, butterflybush, blue spirea, beautyberry, boxwood, and other variably hardy plants are showing the effects of what a deep drop in temperature can do. Leaf emergence on lower parts of plants indicate they were not killed outright but significant growth has been lost.

Utilizing best management practices will nurture this new growth emerging from the lower parts of plants. Given last year’s drought conditions, making sure trees and shrubs are adequately watered, about one inch per week, will help. If irrigating, this one inch of water should be made all in one application, not divided into several smaller ones.  Mulching 2-4 inches deep with wood chips or shredded bark protects plant root zones throughout the year. Refrain from fertilizing trees and shrubs. Stay away from using any lawn weed herbicide containing dicamba. Cutting back stems thought to be dead can be delayed for another week or so to allow ample opportunity for new growth to emerge. For plants deformed by the frigid cold, removing them altogether may be the best option. 

Herbicide Drift

Twisted new growth, stunted leaves, and distorted flower buds—these are the symptoms of herbicide drift. Auxin-containing herbicides such as 2,4-D and dicamba are easily carried on wind currents when wind speeds surpass 10 mph or can spread when vapors lift from targeted plants at temperatures 80° F and warmer.

The degree of harm to plants from drift depends on the age of the plant and the amount of product the plant is exposed to.  Leaves that are smaller than normal and/or are curled do not photosynthesize to their full capability. This means leaves will produce less sugars, which are necessary to fuel root development and fruit production. Young trees have a tougher time weathering herbicide drift than older well-established trees, largely because young trees have a lot of growing left to do, and loss of leaf material greatly reduces the tree’s ability to complete this process. Vegetable plants, like tomatoes, may survive herbicide drift but will have reduced yields. 

There is nothing to be done to counter the effects of herbicide drift. If new growth in vegetable plants continues to be distorted, plants should be removed. Trees and shrubs are not necessarily killed by a single case of herbicide drift, but negative effects accumulate when trees are continually exposed.  Specialty growers, tree nurseries, growers for farmers markets, grape growers, and beekeepers can register their site with DriftWatch™ Nebraska <ne.driftwatch.org>, a communication tool to enable producers and applicators to work together to protect crops.

Road Dust

If you live on or near a gravel road, the dust generated from traffic is more than just annoying. Reduced driver visibility, breathing problems and eye irritation to humans, pets and livestock, reduced life to car parts and machinery, and increased cleaning costs are just a few of the many problems associated with road dust. The amount of traffic, the weight of the vehicles, and the traffic speed determine the amount of dust generated.  According to the Environmental Protection Agency (epa.gov), road dust accounts for the largest source of particulate air pollution in the country.  Besides dust suppressants applied to gravel road surfaces, plants can be a part of the solution, with windbreaks providing filtration by slowing wind speed and allowing dust particles to settle.

Planting a windbreak to protect people and structures from road dust is an important management technique.  Dust is not specific to summers only, so trees and shrubs that are evergreen or keep their leaves through the winter are good choices. Where space allows, two rows of vegetation (one of trees and another of shrubs), at a minimum, will provide better dust filtration than one row alone. Where space allows, planting more rows provides increased dust filtration. Regardless, if the windbreak is for winter protection or road dust filtration, the principles for establishing a windbreak are the same (nfs.unl.edu). 

Plants provide other benefits to gravel roads. Road surfaces shaded by nearby plants lose water much more slowly than their full-sun counterparts, resulting in less road dust.  The roots of roadside vegetation stabilize ditch banks and prevent erosion.

While plants are good at providing air filtration, road dust does pose health problems to plants too. Depending on the rock used on roadbeds, dust generated can accumulate in gardens, changing soil pH. This may or may not pose a problem for plants, depending on the existing soil pH and whether the rock material is acidic or basic.  Where dust blankets vegetation, leaves are shaded, and sunlight is unable to penetrate. With the process of photosynthesis hampered, plant growth becomes stunted. Dust also clogs the plant’s breathing structures, the stomates (in leaves) and lenticels (in wood stems and branches).  Clogged breathing structures mean plants are unable to efficiently take in carbon dioxide and exhale oxygen. Reduced intake of carbon dioxide interferes with the process of photosynthesis, negatively impacting nearby trees, shrubs, and other plants by reducing their growth.

Dust readily washes off plants and buildings with rainfall, but the particles become part of the sediment load as water carries particulates into creeks and ponds, reducing water quality. This will also negatively impact what plant and animal species grow there—a whole other issue in itself.

Great Plants for the Great Plains

Each year, the Nebraska Statewide Arboretum, along with the Nebraska Nursery and Landscape Association, highlight plants that are exceptional additions to Midwest landscapes.  Plants are chosen not only for their beauty but also their durability. Those headlining 2021’s picks for Great Plants for the Great Plains include:

Tree of the Year: Hackberry, Celtis occidentalis. This close relative of the elm is Dutch elm disease resistant and tough-as-nails with beautiful bark and outstanding form. It grows well in a variety of soils and windy conditions.

Conifer of the Year: Eastern white pine, Pinus strobus. This is a soft needled pine and not as prone to problems with pine wilt as other pines are. This is large tree, reaching a height of 60 feet or so with a spread of 30 feet.

Shrub of the Year: Chiquita Sargent viburnum, Viburnum sargentii ‘Chiquita’. White flat-topped flowers are followed by red fruits, with the shrub reaching the size of 6 feet tall and wide. Good for windbreaks, hedgerows, or as a specimen in front yards, ‘Chiquita’ features yellow-orange fall leaf color.

Perennial of the Year: Swamp milkweed, Asclepias incarnata. Like many milkweeds, swamp milkweed is a favored food for both adult and larval stages of the monarch butterfly. Flowers are pink atop 3-foot-tall plants.  Well suited to wet places as its name implies, swamp milkweed can also be grown in well-drained soils and full sun.

Grass of the Year: Morning Light maiden grass, Miscanthus sinensis ‘Morning Light’.  ‘Morning Light’ gets its name from the small band of white at the leaf margins, giving them a silvery appearance. Featuring graceful arching stems and flower heads with a hint of red, ‘Morning Light’ is considered one of the most beautiful of the maiden grasses.  Overall, this clump-forming grass can reach 6 feet in height when in flower.

While the Midwest can be a challenging place to grow plants, the Great Plants for the Great Plains program highlights the best variety of plants, both native and adapted, to grace our landscapes.

Pollinators and Pollinator Gardens

Pollinators and pollinator gardens are the focus of the next GROBigRed Virtual Learning Series. Nebraska Extension Educators in entomology and horticulture will teach participants about steps to take so pollinators thrive—both from flowers and plants important to their health to insect-friendly garden practices to implement.  Why are we concerned about pollinator health? Pollinators are first and foremost critical to our food supply. Most notably, some of our favorite fruits and vegetables, like apples, peaches, cucumbers, and beans, would not exist without our pollinator friends.

Just have a balcony-sized garden space?  The good news is research indicates no gardening space is too small to foster pollinator health. Your garden, when combined with the neighbor’s garden, nearby creeks, and prairie spaces, add to the collective whole. So limited space excludes no one from contributing to pollinator health and this series will provide the know-how to get started.

The first class will be held May 4 at 6:30 pm.  “Creating a Pollinator Habitat” focuses on design and the necessary components to include in the space, such as water, shelter, and food. Other components of the class will emphasize the need for good gardening practices, for instance when to cut back spent perennial stems and how to reduce pesticide use.

On May 11 at 6:30 pm, “Bees, Butterflies, and Beyond” will speak to the whole array of pollinators, including bees and butterflies, but also wasps, flies, and beetles and their contribution to pollination. Insect life cycles will spotlight why it is important to implement practices that save insect lives and ultimately enhance their environment. 

At 6:30 pm on May 18, “Pollinator Blooms for All Seasons” will highlight outstanding plants to include in the garden, most notably for the nectar (a carbohydrate source) and pollen (a protein source) they provide to pollinators and their progeny. Having plants in bloom throughout the growing season ensures food is available to pollinators when they need it.

There is no charge for the series, but registration is necessary to have the links emailed to you: https://go.unl.edu/pollinatorgardening .

Growing Strawberries

Summer’s first tasty bite of fresh ripe strawberries is enough to convince many to try their hand at growing this delicious fruit for themselves. 

The first consideration—what type of strawberry to grow—depends on your picking preference. June-bearers produce a bounteous crop in June and July. Ever-bearers can have multiple crops depending on your location and the growing conditions—one in spring with the possibility of several more crops through the season. Day neutral strawberries like cool moist conditions and will yield fruit regularly when these conditions are met. Of these 3 types, June-bearers have the best overall yield each growing season.

Choose a reliable nursery to ensure varieties are disease-free and accurately labeled. Starter plants can be purchased in bundles of bare root dormant plants or as actively growing potted plants. Look for varieties that are not only tasty but winter hardy as well. June-bearing varieties ‘Honeoye’, ‘Earliglow’ and ‘Cavendish’ fulfill these requirements, while ‘Ogallala’ and ‘Ozark Beauty’ set the standard for ever-bearers. Alpine strawberries, like ‘Tristar’ and ‘Tribute’, are short-lived day neutrals.

Be sure to site the strawberry patch where it gets lots of sunlight—10 or more hours of direct, uninterrupted sunlight daily for best production. A strawberry patch located on higher ground will have less problems with late frosts and water ponding around plants. Higher ground also provides better air circulation for timely drying of leaves which will cut down on some fungal disease problems, like leaf blight and gray mold, that thrive in still air. A loamy soil with lots of organic matter will get plants off to a good start. If organic matter is lacking, work into the soil some compost, well-aged manure, leaf mold, or decomposed straw. 

Space strawberry plants 18-24 inches apart in rows 3 to 4 feet apart. Strawberry flowers and groundcover growth habit means plants can also be enjoyed in an edible landscape when grown at the edges of flower beds.  As a groundcover, strawberry plants may be planted in a 1 foot by 1 foot grid pattern. No matter what type of bed devised for strawberries, plants should be planted so the midpoint of the crown is even with the soil surface. Planting them too shallowly or deeply means plants will dry out or be smothered, which is not good for plant survival.

For more information on weeding, diseases, insect pests, and winter care of strawberries, follow these links: Growing strawberries in the home garden | UMN Extension and Growing Strawberries in Wisconsin.

Staking Newly Planted Trees

Confusion surrounds the healthiest way to stake newly-planted trees to stand up to fierce winds while fostering good root growth. The old method, seen much too often still, of snaking wire through a section of garden hose to wrap around trunks and branches is highly injurious to trees. This ill-advised technique digs into tree conductive tissues and, left in place too long, shuts down sugar transport from the leaves to the roots. Roots then become starved of sugars necessary for certain functions, like existing. 

Small trees, those less than 5 feet tall and not in windswept conditions, may not need any staking at all. Realistically, we live in an area associated with lots of wind, so when staking trees, there are several good ways to stabilize them that are less likely to cause long-term damage.

•Stake new trees using broad strapping material, made of burlap, denim, nylon mesh, or canvas. A strap is wrapped around the tree and the ends of the strap are mated together. Then wire or rope is threaded through holes punched in the strap ends and attached to a nearby stake. Small trees are stabilized with just one stake while two to three stakes can be used for larger trees. If possible, the position of the strap should be located on the lower 1/3 of the tree to allow trunk movement, which is necessary to develop a strengthening trunk taper while still stabilizing the root ball. Wooden stakes, appropriate for smaller trees, should be at least 2 inches by 2 inches. In areas of high winds or with larger trees, metal fence stakes should be used. As a safety concern, stakes should always be placed within the tree’s mulch bed to increase their visibility. Staking too high or too tightly leads to trunk breakage and tree failure. As a final step, staking materials should never be left on for longer than one year. Be sure to mark the calendar to ensure this important task is completed.

•Research by Colorado State University Extension on the underground stabilization technique uses two to three wood dowels driven through the edge of the root ball into the ground. This prevents rotation of the tree’s root ball and no additional staking is required. There are no materials to remove later as the dowels will decompose over time.

Along with watering during dry periods and utilizing 2-4 inches of wood chip mulch around newly-planted trees, good tree establishment is ensured when trees are staked correctly.

Spring Tree Care

Spring’s re-birth of all that is green is a good time to assess how trees and other landscape plants made it through winter. Many evergreen trees, such as spruce, are exhibiting signs of winter burn, with browning and bronzing of needles.  Winter’s deep cold and strong winds dried out plant tissues, resulting in loss of evergreen needles and dieback of branches in deciduous trees. This dieback is a function of the tree’s survival mode, allowing needle loss and twig dieback so that the rest of the tree may survive.

Tasks tree owners can do to help trees, both evergreen and deciduous alike:

Water deeply and infrequently. For those with an irrigation system, it is likely the turfgrass is receiving adequate water, but trees are not. Most irrigation systems water shallowly and frequently, keeping upper soil layers saturated while the tree’s lower roots remain dry.  Use a screwdriver to determine if water is reaching lower soil layers—one easily pushed into the soil indicates water is soaking in. Remember to do a deep soaking prior to ground freeze in the fall.

Mulch.  A 2–4-inch layer of an organic mulch, such as shredded bark or wood chips, replicates what nature creates on the forest floor. Known as duff, this accumulation of twigs, leaves and other organic debris fosters rich microbial activity beneficial to tree roots.  Landscape fabric, rubber tire mulch and rocks do not support microbial growth, keep root zones hotter, and do little to help trees. 

Do not fertilize. If the lawn is regularly fertilized, then trees are receiving adequate nutrition for good health. Fertilizers injected into the soil and fertilizer spikes foster leaf growth in trees but force trees to neglect needed functions like root growth and pest resistance. Fertilizer spikes in particular burn roots, causing root dieback.

Prune trees to remove rubbing branches, hangers, and double leaders.  These areas promote decay, making trees susceptible to damage from wind and snow loads. Never prune trees for the sole purpose of allowing in sunlight to grow better grass beneath. Thinning out tree canopies alters tree aerodynamics, increasing the potential for wind damage.

Remove some of the lawn.  Turfgrass competes with trees, especially young trees, for water and nutrients. By removing grass to a distance four feet from the trunk, trees will grow faster and be healthier overall. Do not forget to follow up the grass removal with mulch.

Don’t forget the old trees. One common mistake is to believe old trees need no care at all. Foresters tell us that there is a five-year lag to tree stress, often not becoming apparent until trees are exhibiting noticeable symptoms, often too late to counter.  This means 2020’s drought will negatively impact trees until 2025, increasing the likelihood for insect pests and disease problems to gain a foothold. While older trees have stronger, more developed roots to access water during dry spells, drought conditions mean lower sources of water in the soil are gone. Mulching and deep, infrequent watering are vital to older trees too. 

Raising Awareness of Pesticide Drift

DriftWatch® and BeeCheck® are two resources available to the people of Nebraska to register their specialty crops and beehives. Likewise, pesticide applicators can sign up with FieldCheck® to view maps and receive notifications of sensitive crops and apiaries in their region. Sign up for producers, beekeepers and pesticide applicators is voluntary, with the goal to promote awareness and reduce pesticide drift. 

This communication tool was originally developed by Purdue University and has spread across the country. The program provides verification of each producer’s submittal for their site. For applicators, the website is a tool to determine sensitive sites before they spray. Producers can register their sensitive crops, including grapes, fruits, orchards, vegetables, industrial hemp, nut trees, fish farms, beehives, and high tunnels, just to name a few, as well as crops certified as organic.  The web page’s interactive maps allow registered applicators to zoom in at the county and community level, scrolling over sites to determine what specialty crops are there.

A word about pesticides. “Pesticide” is an umbrella term encompassing all products that repel or kill pests. Under this definition, herbicides, rodenticides, fungicides, and insecticides are all pesticides. Producers who register their crops with DriftWatch® do so with the intention to provide protection from the full range of pesticides that can drift onto their site.  Specialty crop signs may be purchased by registered producers and beekeepers.

DriftWatch® is sponsored by the Nebraska Department of Agriculture’s Pesticide Program. Information about DriftWatch®, BeeCheck®, and FieldCheck® is found at https://ne.driftwatch.org .

Winter Damage to Evergreens

Spring’s welcome temperatures give us a chance to walk the landscape, checking to see how our trees and shrubs weathered the winter. Rabbit feeding damage on burning bush, vole paths over the lawn, and browning of evergreen needles are some of the things you will notice.

Evergreens have the unique ability to photosynthesize when temperatures reach 45° F, which seems odd but can and does occur during our winters.  Tree roots in frozen soil, as is often the case during our winters, means photosynthesis is using water that evergreens cannot replace.  The result is brown needle tips that can encompass all the leaves on the south side of the tree. (The Northern Hemisphere’s tilt away from the sun during the winter months makes this possible.)  The drying effects of bitterly cold winter winds also dries out foliage. Tree owners and tree services alike are reporting lots of tip browning of evergreen needles this spring, primarily of spruce trees.

The time to prevent needle browning is in the fall of the year. Tree owners should take note, making sure the soil is evenly moist prior to ground freeze.  This ensures tree tissues are well-hydrated.  The screwdriver test is the easiest way to check soil moisture levels when ground is unfrozen. A screwdriver blade difficult to push in is indicative of dry soil, while a blade that pushes in smoothly indicates good soil moisture.

Newly planted trees are the most severely affected by winter’s dryness, having less established roots to mine the water they need. Besides, watering, newly planted trees benefit from the application of an anti-desiccant in late fall.  Anti-desiccants are spray-on products that contain wax or plastic to thinly coat needles and broadleaf evergreens, reducing the amount of winter water loss from drying winds and warm days. Anti-desiccants should be applied twice, once in late fall and a second application in mid-winter, and only on days in the 40-50° F range.  More information about anti-desiccants is found here: https://ag.umass.edu/landscape/fact-sheets/protecting-evergreens-in-winter-qa .

There is nothing that can be done to force evergreen needles to re-gain their green color. Evergreens shed needles when the leaves are not photosynthesizing efficiently. The best thing to do now is to practice vigilance and water trees when there has been more than a month of no precipitation (or use the screwdriver test to check soil moisture levels). Refrain from fertilizing trees as this can deepen the effects of winter injury and summer drought. Snow melt can skew our perception of just how dry things are, indicating the importance of checking soil moisture. The U.S. Drought Monitor has large portions of Nebraska in the Abnormally Dry to Moderate Drought conditions:   https://droughtmonitor.unl.edu/ .

Vole Damage

“What are these trails in my lawn?”  This is a common question once snows recede.  Pathways interspersed throughout the lawn are an indication of the presence of voles. What are voles, you ask? Voles are rodents with an appearance very similar to mice except for their tails which are about 1 inch long.  Voles are granivores and paths may be more apparent around bird feeders, where fallen seed attracts them.

Voles create trails on the soil surface, beneath the snow layer, to stay out of the watchful eyes of predators.  They are active throughout the winter, thus providing a surprise to unaware home dwellers when snows melt. Two things contribute to the trails they make. Voles will chew off the turfgrass leaves and crown to make their way through and they also tend to run in single file, wearing down thatch and anything else in their way.  The turf loss is alarming but not permanent especially once the growing season returns and then the grass fills in.

Vole damage can be a concern, however, if rock retaining walls are a part of the landscape.  Vole tunneling behind rock retaining walls can undermine the structural stability, causing wall collapse. In addition to tunneling, vole feeding can cause permanent damage to fruit trees, new trees and planted bulbs. As seeds and grains become scarce in later winter months, voles will resort to eating tulip bulbs and roots and crowns of trees. Young trees, having limited roots systems, will have significant dieback and even death from vole feeding.

Regular snap traps, baited with peanut butter and birdseed, will manage vole populations. Traps should be place perpendicular to their trails, with the trap snapping towards the trail. Snap traps will work just fine if there are no pets that can accidentally get caught in them, otherwise a box trap will be a better choice. Box traps are live traps, no bait needed, and placed in the pathway itself. Check the box trap regularly, relocating caught voles to new locations or dropping the trap into a bucket of water to drown them.

Keep in mind the mighty-but-small shrew will enter vole tunnels with the express purpose of eating voles. If you should capture one of these little guys in a box trap, be sure to release them back into the yard to continue their work. They may be a lot smaller than voles but that doesn’t deter shrews from making quick work of them. Mulch piled against the bark of trees and shrubs affords voles the opportunity to do damage to roots and trunks. Mulch should be piled no higher than four inches and never against the base of trees and shrubs. Hang bird feeders over paved surfaces and periodically sweep up fallen seed to remove food sources that attract voles.

More information about voles and their management may be found at:  https://extensionpublications.unl.edu/assets/html/g887/build/g887.htm .

Using Annual and Perennial Flowers to Boost Curb Appeal

When we think of flowering annuals and perennials as limited resources, using them wisely contributes to maximizing curb appeal. After all, not everyone has unlimited budgets or time to have flower color everywhere.

A word about the color green—green piques our interest in the winter and early spring landscapes, most notably because there is so little of it around (think evergreens and patches of lawn showing through the snow.) That perspective changes as landscapes green up in the spring and THEN green switches from being a focal point to becoming a background color. This transition is important because flowers show to their best advantage when placed in front of a backdrop of green.

Landscape design aspires to take its cues from Mother Nature, with an overstory—consisting of large and medium sized trees; an understory—utilizing small trees and large and medium sized shrubs; and groundcover made up of small shrubs, annuals, and perennials. This makes annual and perennial flowers important components in landscape design.

Annual flowers need to be planted every year, but on the plus side, they reward us with season long color. The most important place to use annuals, regardless if they are in containers or planted in the ground, is near the front door. From the perspective of the curb, the front door is the focal point, and the season long flowers annuals provide mean colors will continue to draw attention to the front door.

Perennial flowers, with their winter hardiness, are blooming show-stoppers, even though flowering lasts about two weeks each year. Perennials can and should be added to flowering plant masses near the front door, but one or two plants alone do not provide the massing necessary for the orchestration of color season long. In cases where space is limited, grouping a few perennials with an annual or two helps to boost the level of color while providing a backdrop of green.

Annual and perennial flowers don’t just look pretty—they benefit pollinators and songbirds, contribute to biodiversity, act as a guide as we move through landscapes, elicit emotions of joy and calm, and reinforce focal points. While planning your gardening season, remember to add flowers to your list!

Annual and Perennial Flowers

Growing a vegetable garden versus growing a flower garden can be hotly debated. Vegetable gardeners ask, “What good is it if you can’t eat it?” Flower growers think if it is not pretty, what’s the point? For me, growing both vegetables and flowers are necessary—vegetables nourish my body while flowers feed my soul.

As the calendar pulls us towards March, gardeners can be assembling the seeds and materials to start their own annual flowers.  The variety and number of plants are as wide as the array of available seed and is not limited by the ready-to-plant cell packs at garden centers. Keep in mind, too, that the garden industry itself caters to the newest introductions, bypassing beloved past introductions and heirloom types to foster excitement.  This means some older varieties are only available as seed and your purchasing dollar provides the “votes” to incentivize growers to continue to offer them. All-America Selections is a trialing organization that releases plant introductions exhibiting outstanding performance.  Their webpage lists current introductions as well as those going all the way back to 1933! www.http//all-americaselections.org .

Saved seed provides gardeners with more opportunities to grow favorite plants.  While the seed may be harvested from hybrids, gardeners can still try them out, looking for surprises in flower color, disease and insect resistance, and plant form.

Don’t be too anxious to remove mulch around perennial flowers and plants. Some warm days may push sprouting, but this is the Midwest and more deep freezes are ahead. Removing mulch too early exposes plant crowns to possible freeze damage.  Wait until April, when frosts won’t pose a problem for perennial flowers like a hard freeze would.

And if you’ve held off growing flowers because of the whole vegetables versus flowers debate, remember there are edible flowers you can grow. Not only are they nutritious but they really pretty-up a plate.  I’ll never forget my hostess’s gorgeous plate of daylily flowers stuffed with chicken salad. Who new daylily flowers were edible? An excellent list of edible flowers is found on the University of Minnesota’s Extension website:  https://extension.umn.edu/flowers/edible-flowers .

Seed Starting & Indoor Lights

The GROBigRed team is kicking off 2021 with some exciting new virtual learning options for gardeners across Nebraska.  We’ll be starting with a double header on January 30 with Seed Starting (instructor: John Porter) and Indoor Plant Lights (instructor: Scott Evans).  Please share with your clientele and through your social media channels.  Graphics for social media, emails, or newsletters are attached.  Link to a shareable Facebook post is below. 

The program is free.  Sessions will be recorded and shared with those who are registered (even if they can’t attend live).

Registration link: https://go.unl.edu/startseeds

Shareable Facebook Post: https://www.facebook.com/UrbanAgNebExt/posts/3753922837987192

When Ice Damages Trees

Ice by itself doesn’t damage trees, but the accumulation of ice on branches creates loads that can and do result in branch breakage and complete tree failure. Case in point is the recent ice storm, creating ice coatings of ¼ to ½ inch over most tree branches. This is a tremendous amount of weight to add to trees and while structurally trees develop to handle wind and snow loads, extreme events like ice accumulation and derechos really throw a wrench into tree structural stability.

When it comes to clean-up after a storm event, “hangers”, those limbs that are broken but remain partially connected to the tree, should be removed first, especially if the hangers threaten roofs or people who may be passing below.  The ideal time to prune is in April, May or June, when small reaction zones within trees makes for timely wound closure. If a storm damaged tree has sentimental value or is an important part of the landscape, hangers can be removed now but ask your arborist about completing the finished cuts and final pruning in April, May or June to promote the tree’s timely wound closure from pruning cuts.  Skip any products that tout wound protection when applied to pruning cuts.  These aren’t effective and actually benefit decay microorganisms.

Much of the ice damage was particularly hard on branches and trunks with included bark. Included bark is the condition where bark gets pinched between two competing limbs or stems that are close together, creating an environment ideal for decay to develop and weakening branch attachment.

Be aware that the pruning practice of lions tailing contributes to tree failure. Lion’s tail pruning concentrates the tree canopy to the ends of branches. Snow and ice loads accumulated at the ends of branches will have greater leverage to surpass the tree’s structural capabilities and branches will break. 

To ask questions about your trees, you can contact me, Kathleen Cue, at the Dodge County Extension Office at 402.727.2775.

Landscape Fabric

Whether you use landscape fabric beneath mulch in outdoor spaces depends on what you know about it. The two main reasons landscape fabric is used are A) a desire to keep weeds down and B) employing any means necessary to keep rock mulches from sinking into the soil after a rain. Unfortunately, neither of these reasons assures landscape fabric will function as planned.

Here is why. 

Landscape fabric is a temporary weed barrier, suppressing weeds for a few years. Ultimately soil and seeds blow in, settling over the fabric and creating the perfect environment for seed germination. Emerging weed seedlings send roots through perforations in the landscape fabric, growing their merry way downward. When these weeds are pulled, roots pushing through the landscape fabric will cling to the fabric as well. Then weed removal entails disentangling roots from the landscape fabric, which has been pulled up too. Once weed development becomes an issue, weed problems are ongoing because of continuing accumulation of soil and weed seeds above the fabric.

The second reason not to use landscape fabric, and a more compelling one, has to do with creating a healthy growing environment for desired plants to thrive. All plant roots respire as part of their natural growth and development, taking in oxygen and giving off carbon dioxide. This exchange of gases, as it is called, is interrupted by the presence of landscape fabric and rock mulch. The results are less plant vigor, more plant stress, and less natural defenses to ward off insect and disease problems. If you have ever removed landscape fabric, it was likely the soil beneath was slimy, a sure indication of a poor growing environment for plant roots.

Are there instances where landscape fabric has an application? Yes. In windswept environments, landscape fabric and rock mulch may be the only thing protecting plant roots. Master Gardener Lynn had just such a situation, with the wind rounding the corner of his house with the fury of a wind tunnel.  Everything planted near this corner died, with wood chips and soil blowing away, exposing plant roots. He found landscape fabric and rock mulch were the only things immune to the wind and protective of plant roots. Lynn eventually converted the space over from landscape fabric and rock mulch to solely wood chips, once a nearby windbreak grew enough to provide protection.

When planning your landscaping projects, consider landscape fabric as one expense to do without. Not only will this save you some money and effort, but your plants will thank you with increased health too.

Fall’s Red Leaves

Glorious golds are fall’s main colors in our region, helping to foster appreciation for autumn reds, which tend to be rarer. Instead of adding the over-utilized ‘Red Sunset’ and ‘Autumn Blaze’ maples to your landscape, diversify the neighborhood and community by choosing from fall’s red leafed trees that are not maples. When a variety or species is overplanted, it makes way for certain insects and/or diseases to run rampant, much like emerald ash borer is for ash trees and pine wilt in pine trees. Some ideas for fall red-leafed trees include:

Pagoda Dogwood, Cornus alternifolia

This small tree is great for urban landscapes, reaching just 20 feet in height with a similar spread. Fall color is reddish, mixed with some purple.

Sweetgum, Liquidambar styraciflua

Fall color in the sweetgum is gorgeous shades of red, gold, and purple. This tree can reach a height of 45 feet and a width of 30 feet. The fruit of the sweetgum is not for the faint-hearted, producing spiny 1-inch balls that are not fun to step on in bare feet when getting the Sunday paper from the front stoop. Trees should be planted well away from paved surfaces to get around this issue.

Black Tupelo, Nyssa sylvatica

Black Tupelo, also known as black gum, should be transplanted as a small tree, due to its reputation for being difficult to establish when planted as a large tree. Trees can reach 40 feet in height at maturity and fall color is a mix of yellow, orange and red.

Shumard Oak, Quercus shumardii

While closely related to the pin oak, this lovely upright oak does not have issues with high pH soils as pin oak does. Shumard oak grows to 40 feet, with a similar spread. Fall color is russet-red to red.

Sassafras, Sassafras albidum

One of the best native trees for fall color, the sassafras has mitten-shaped leaves in fall colors of yellow to orange and red to purple. Tree height ranges from 30-50 feet. Like the black tupelo, the sassafras should be transplanted as a small tree to establish successfully.

Shrubs

Don’t forget red colors can be added to landscapes in the form of shrubs.  The burning bush (Euonymus alatus), black chokeberry (Aronia melanocarpa), Firedance™ dogwood (Cornus sericea ‘Bailadeline’), Autumn Inferno™ cotoneaster (Cotoneaster ‘Bronfire’), dwarf fothergilla (Fothergilla gardenii), Jetstream™ oakleaf hydrangea (Hydrangea quercifolia), and many varieties of viburnum are excellent additions for fall’s red colors.

Fall Perennial Plant Care, Part Two

It may seem like perennials demand lots of our attention, but they are really quite forgiving, with many plants living despite, not because of, our gardening efforts. For their hardiness and beauty, we can ensure they stick around by adhering to a few guidelines.  

Digging and Dividing

If your perennial plants didn’t bloom well or they’re crowding their neighbors, fall is an excellent time to divide plants. Some perennials, like ‘Karl Foerester’ feather reed grass, develop woody centers at the crown over time. These areas have lost their vigor and no longer send out growth, despite being dense with plant tissue. Using a sharp spade, dig the entire clump and divide the root system, being sure each division has a crown and roots, discarding the center of the plant to the compost pile. Make sure clumps are at least 6 inches across to ensure good vigor once the division has been planted.  Set the divisions in their new location, making sure plants are at the same depth as they were previous to digging. For plants like peonies, this step is critical because plants too deep or too shallow will not bloom again. Cut back foliage by half so the reduced root system's water uptake matches leaf needs. Water the transplants in their new location and mulch to delay ground freeze which allows more time for new roots to develop.

Fertilization

If your soil is clay, then adding fertilizer to your soil is not necessary for the health of your perennials.  Clay soils have a high cation exchange capacity (CEC), meaning each clay particle has lots of locations to hold nutrients for good plant nutrition. Sandy soils are a different story because sand does not hold onto nutrients (low CEC) like clay soils, with nutrients leaching away with rainfall. Both sandy and clay soils benefit from mulches as they decompose, adding nutrients and organic matter to the soil.

Fall is For Planting

Fall is a great time to take stock of landscaping "holes". These are areas that had plant loss or could use sprucing up. Perennials planted in fall establish well, when warm soils foster good root growth.  Increasingly, gardeners are planting perennials that serve purposes beyond their simple beauty--supplying nectar, pollen and seeds for pollinators and birds, fostering drainage in rain gardens, and serving as traps for blowing snow. Spring flowering bulbs are by their very nature perennials, deriving their survival not from a root system as perennials do, but from underground stems. Tulips and daffodils are classics, but consider adding some of the lesser bulbs like grape hyacinths, glory of the snow, Siberian squill, dogtooth violet, crocus, and summer snowflake, providing food for pollinators when few things are in bloom.

With a few steps, perennial plants will continue to add beauty and joy to our landscapes. Happy Fall!

Fall Care of Perennials

Once gardeners and gardens have survived the heat of summer, cooler weather offers an opportunity to complete some simple tasks to ensure perennial plants emerge in good health next spring.

Cutting Back

If the foliage of perennials has been disease-free, wait to cut them back until spring. This benefits our native bees because 1/3 of native bees overwinter in cavities, which includes the hollow stems of plants. By waiting to cut back perennials until spring, these pollinators are given a fighting chance to survive. In addition, many perennials are beautiful in the winter landscape, showing off the petal-less cones of purple coneflower and the gracefully waving seed heads of prairie dropseed. Stems left in place serve as reminders where the slow-to-emerge balloon flowers and hibiscus will be in spring. Stems catch leaves and other bits of plant debris, making them self-mulching.

Deadheading and Clean-Up

Perennials that are aggressive self-seeders should be deadheaded in the fall to cut down on the number of volunteer seedlings in the spring. Perennials like garlic chives have charming flowers but the number of seedlings one plant produces is alarming. On the other hand, coneflowers provide seeds to overwintering songbirds and should be left in place. Daylilies present a ragged appearance after blooming, so gently tug out dead leaves and spent flower stalks. The brown tips of the long leaves can be trimmed away. Fungal spores of powdery mildew and botrytis overwinter on standing stems of peonies, so clean up to reduce inoculum for next years' plants is helpful.

Watering

Perennials need an inch of water per week. This year's drought conditions have not abated, even in locations where rainfall was 4 inches or more. Before ground freeze, water plants so the entire area receives an inch of moisture. Use straight sided cans, like tuna fish or cat food cans, when irrigating to provide guidance when this one inch of water is achieved.

Mulching

One of the many benefits of mulch is to serve as a barrier from quick air temperature fluctuations. Most perennials nicely withstand deep drops in temperature--as long as changes occur gradually.  In the Midwest, this can be a challenge even for the toughest perennials. Mulches trap protective air pockets around roots, buffering the effects of quick temperature changes. Wood chips, shredded bark, straw, pine straw and grass clippings are good mulching materials. Rock is not a good mulching material because it readily transfers the air temperature to roots, making roots susceptible to cold injury when temperature change is swift. Layers of wood chips should be no deeper than 3 inches and placed about 2 inches away from plant crowns to ensure good air circulation. Add mulch to maintain this 3-inch depth as it decomposes.

Watch for a continuation of Fall Care of Perennials, when the topics of Fertilization, Digging and Dividing, and Fall Planting are covered.

Poison Ivy or Poison Oak?

Identifying poison ivy can be perplexing, mostly because the leaves can look different from one plant to another. There is some variation in how the plant grows, too, with it sometimes looking like a groundcover, other times a shrub, and still others a vine.  Those not familiar with the variations in the plant can have irritating results when hiking through thickets and stands of trees. The only thing consistent about the appearance of poison ivy is referenced in the adage “leaflets of three, leave them be”.  From there, the appearance varies greatly from plant to plant. The term “ivy” indicates the plant is a vine, but a clump of poison ivy growing on the edge of my gravel road has the look of a groundcover, reaching just 6 inches in height. The vining characteristics of poison ivy do not become apparent unless there is something for the plant to climb, like a nearby tree, shrub or fence.  Small hair-like structures on the stem, known as aerial roots, are the mechanism for poison ivy to gain a toehold in the smallest of cracks and begin climbing. Leaflet edges can have large serrations with the two outside leaflets resembling a pointed mitten and the central leaflet looking like a mitten with two thumbs. Occasionally, poison ivy will have no serrations on leaflets, a confusing thing indeed, but a quick check of the leaf arrangement and poison ivy will have leaves arranged alternately along the stem. Boxelder seedlings can look amazingly like poison ivy but the leaf arrangement will be opposite instead.

Poison oak resembles poison ivy, with the leaflets arranged in threes but it differs in that the leaflets are lobed, not pointed, and will resemble oak leaves. The real question of poison oak is does it grow here? It’s not likely, since the furthest north it grows in the Midwest is Kansas and Missouri. There may be pocket microclimates where poison oak overwinters in sheltered locations, but the plant doesn’t naturally occur this far north, so any stands of poison oak that might exist will be small in comparison to the robust winter-hardy stands of poison ivy found around here.

The misery-causing component of poison ivy, called urushiol, is persistent and exists in all parts of the plant. A brush killer is best for controlling poison ivy, utilizing a paint brush to apply the herbicide when desirable plants are nearby.  Personal protective equipment keeps the applicator safe from the herbicide and the urushiol.

poison ivy

Fall Weather Patterns Predict Early Freeze, Deepening Drought

The National Weather Service’s Climate Prediction Center has some startling news for September 12 through the 15th—a cold front moving through the central Great Plains region will bring falling temperatures, with a moderate risk of these temperatures being below freezing. How far temperatures fall is dependent on just how cold the cold front is and how much water is in the air (the dew point.) Dry air fluctuates more readily from hot to cold temperatures than moist air does. This follows through with soils too, with cold temperatures extending deeper into drought stressed soils than wet ones.

Typically this region doesn’t see a damaging frost until around October 10. Fruits and warm season vegetables like tomatoes will be hit hard by freezing temperatures. Covering un-harvested crops traps warmth around plants and acts as a physical barrier to freezing temperatures. Several layers of plastic or bed sheets do better at trapping warmth than a single layer. Buckets can be inverted over tall plants with a brick or rock on top to keep the bucket from toppling. More information about the predicted freeze may be found here: https://www.cpc.ncep.noaa.gov/products/predictions/threats/threats.php .

With drought conditions deepening, getting out the garden hose and the watering can are crucial.  Plants native to the Midwest won’t necessarily need water now, unless they were newly-planted this year. (Well-established native trees, shrubs and wildflowers weather periods of wet and periods of dry.)

Watering Priorities

▪Anything newly planted this season requires attention now. New plants do not have the extensive root system as their well-established counterparts. Drip irrigation does dual duty by watering deeply while losing less water to evaporation. Innovative ways for your own DIY drip system include placing water-filled gallon milk jugs next to plants, with each jug having up to 3 tiny holes on the bottom to provide drip irrigation. For new trees and shrubs, a 5 gallon bucket, drilled with (3) 1/8-inch holes, can be placed over the rootball, then the buckets filled with water.

▪Established plants, like fruit trees, shrubs, trees, roses and perennials need about an inch of water per week. With August being one of the driest on record, deep watering is necessary to reach all of the plants’ roots.  Set the garden hose to trickle and leave it on for extended periods, moving the end of the hose multiple times beneath tree and shrub canopies to reach as many roots as possible.  Another option, an idea provided by Burt County’s John Wilson, is to duct tape a double layer of old socks over the end of the garden hose and turn the faucet on. Water won’t come out in a gush and cause erosion but instead bubbles out with enough aeration to soak in.

▪Lawns comprised of Kentucky bluegrass can be allowed to go dormant during dry periods, provided lawns are given ½ inch of water every third week to keep turf crowns hydrated. Turf type tall fescue avoids drought by developing an extensive root system to tap lower sources of soil water. Once fescue has utilized all of the water within its root zone, however, plants die, so providing 1 inch of water every month during drought is important to keep fescue alive.

For more on wise watering practices, check out this link:  https://water.unl.edu/category/lawns-gardens-landscapes/lawn-landscape-irrigation?mobile=no&page=1  .

The Oak Twig Girdler

The appearance of dead foliage clusters scattered throughout the canopy of oak trees is very noticeable right now. Some of these twig-and-foliage shoots, called “flags”, are breaking away, littering the ground below. This is symptomatic of the oak twig girdler, Oncideres cingulata. Oaks are the most common trees to be afflicted with the oak twig girdler, but other hardwood trees can be affected too.

What is the oak twig girdler (OTG)?  This is a long-horned beetle, ¾ of inch long, with antennae that are as long as its body. The OTG typically emerges in mid-August, with adult females chewing a shallow V-shaped channel that completely encircles the twig, laying one egg in the bark beyond the channel. Hatched larvae bore into the wood to feed, then overwinter in this protected environment even when twigs break from trees. There is one generation of the OTG each year.

What can be done about the oak twig girdler? First, the presence of flags within the canopy and on the ground does little in the way of damage to otherwise healthy trees. Often the full extent of the flagging has reached its peak by the time it is apparent, so insecticides will not be helpful. Clean up of fallen twigs and removing them from the yard will decrease the number of OTG larvae from emerging as adults next year.

Note that most of our trees within the region are living in drought conditions right now.  Watering trees, from the newly planted to the well-established, is of utmost importance.  Placing the end of a garden hose, set to trickle, beneath the tree canopy ensures a deep soaking with little water loss due to run-off or evaporation.

Cucumber Bitterness

The compound that imparts the bitter taste in cucumbers is cucurbitacin. Wild cucumbers have a large amount of cucurbitacin, which discourages feeding by wild animals and insects. Today’s hybrids have been bred to have lower amounts of cucurbitacin in the fruit and what cucurbitacin is in the plant is concentrated in the roots, leaves, and stems. In instances where the bitter compound is in cucumbers, it is more prevalent in the stem end than the blossom end.  This has to do with coloration, since the compound tends to be in the darker green areas of the skin. This is also why cucumbers are sometimes peeled—to rid the cukes of the bitter taste. Misshapen fruit will also have more cucurbitacin than normal-shaped ones.

The cucumber variety as well as the growing environment will contribute to the development of cucurbitacin in cucumbers.  Cool, wet conditions as well as hot, dry weather are major factors.  While weather is beyond our control, providing water during dry conditions and mulching plants are the simplest ways to promote less bitterness.  Deep, infrequent soakings will hydrate the deepest roots, encouraging growth where the soil is cooler.

The social media chatter about pollination by bees leading to the development of bitter compounds in cucumbers (by moving pollen from wild cucumbers to garden cucumbers) promotes a false understanding of how pollination works. If pollen is moved from a wild cucumber flower to a garden cucumber flower, the genetics for the trait of cucurbitacin production will be within the new seeds formed, not the fruit. The new cucumbers will remain true to the variety planted in taste and texture. It is when seeds are saved from this wild-to-domestic cross that there may be a problem, especially to seed savers and seed companies. The plants grown from these crosses will reflect traits of both parents and, if one parent is a wild cucumber, the cucumbers produced could be extremely bitter. Seed companies are well aware of the potential for crossing with wild types and will take necessary steps to remove wild plants from the surrounding area and isolate crops to ensure seeds are true to type.

More information about cucumber bitterness may be found here: https://extension.oregonstate.edu/news/cucumber-bitterness-explained

https://www.purdue.edu/hla/sites/yardandgarden/cucumbers-bitter-during-hot-dry-weather/ .

Yellow Nutsedge

“What is this grass growing in my flower bed?” is a question I hear quite often now.  Rolling the stem between my fingers quickly determines this isn’t grass at all but the infamous yellow nutsedge.  Sedges are grass-like perennials that have triangular shaped stems.   If they grew at the same rate as turfgrass, many lawn owners would be OK with nutsedge growing there. Unfortunately, high heat and abundant moisture foster fast growth that easily outpaces the height of Kentucky bluegrass and fescue.   Yellow nutsedge is a particular problem in new flower beds and shrub borders if the previous space was occupied by turfgrass.  Dense lawns suppress the growth of yellow nutsedge and, once the turf is removed and landscape plants installed, yellow nutsedge can show up throughout. 

The use of “nut” in yellow nutsedge’s name comes from the small tubers, called nutlets, found at the end of roots. The presence of these nutlets helps to explain why the plant is so hard to manage at this time of the year. Removing yellow nutsedge by hand-pulling ensures nutlets will be left behind.  Once each nutlet begins to grow, where once there was one plant, now there are many. Herbicides used now will also be effective at eliminating the parent plant, but bear in mind herbicides do not translocate to the nutlets, so again, where once there was one plant, now there are many.  This isn’t to say we can’t hand-pull or use a herbicide, it just means diligence will have to be exercised to stay after new plants by repeating previous steps.

June 21 (the summer solstice) is the dividing point from when yellow nutsedge is relatively easy to manage to when it becomes a chore. Prior to June 21, plants have not reached the maturity necessary to form nutlets. Lawn herbicides containing the active ingredient Halosulfuron (Sedge Ender™, Sedge Hammer™, and Halosulfuron Pro™) applied before this date will be the most successful at managing yellow nutsedge in lawns. In gardens and borders, yellow nutsedge can be hand-pulled or spot sprayed with herbicides containing glyphosate, being mindful to shield desired plants.

From June 21 onward, the nutlets of yellow nutsedge are a tenacious survival mechanism that requires diligence (or acceptance) on our part to manage yellow nutsedge in our landscapes.

Cedar Apple Rust of Ornamental Pear

Cedar apple rust is a fungal pathogen that gets its name from a life cycle infecting cedar trees, then plants in the Rose family and back again. This year, spring weather conditions promoted the development of cedar apple rust on ornamental pears, such as ‘Bradford’ and ‘Cleveland Select.’ As rust has developed, symptoms are more easily recognized with yellow-haloed orange spots on leaves and early leaf drop.  Tree owners’ questions center on “What is this and how do I treat it?”

It’s important to note that fungicides applied now to ornamental pear will not control rust. Instead, fungicides work best when applications are targeted for early spring, as a preventative. While rust is not attractive, it doesn’t kill ornamental pear. More about timing of fungicide applications may be found on the Back Yard Farmer website: https://byf.unl.edu/cedar-apple-rust .

Rust damage to cedar (otherwise known as juniper) is negligible to nonresistant. Rust causes brown, lumpy galls to form on twigs and branches. In the spring, these galls develop gelatinous orange projections (called telial horns) that release spores to be carried on wind currents, depositing on susceptible species of the Rose family. Treatment of cedar apple rust on cedar is not only unnecessary but treating them proactively to forestall infection on susceptible pear and apple trees isn’t effective, since juniper isn’t just in yards, but also grows in pastures, fence rows and creek banks.

For the alternate host--plants in the Rose family—the species of rust will manifest as spots on leaves or lesions on the fruit and sometimes twigs.  There are more than one species of rust and what Rose family member is affected determines which rust it is:

               ▪Hawthorn (cedar hawthorn rust);

               ▪Apple, crabapple and pear (cedar apple rust); and

               ▪Quince (cedar quince rust).

Unlike cedars, rust on plants of the Rose family can have its downside.  While rust usually doesn’t kill pear and apple, it does affect the plant’s ability to fruit well. Dealing with rust needn’t be a yearly thing—there are plant varieties less susceptible to rust, such as ‘Liberty’ and ‘Enterprise’ apples. While reduced susceptibility never means these selections are always 100% rust free, disease-resistant cultivars are healthier, have a better plant appearance, and fruit more productively than their susceptible counterparts.  

Spruce Trees

Many spruce trees in the area are looking rough. Beyond the usual injury from spruce spider mites and Rhizosphaera needle cast, spruce trees have serious dieback, not only individual branches but in some cases, the top has died.  Drooping clusters of brown needles and streaks of white sap on branches and trunk indicate freeze injury.

While late April is our last average frost date, early May saw a deep drop in temperatures, bringing frost. Much of the new growth in spruce trees was damaged by this cold spell. Spruce trees are well-suited to cold temperatures, but new growth is not. New twigs and needles develop thickened cell walls (called lignification) as they mature, needing the bulk of the growing season to complete this process. Spring’s new growth simply didn’t have enough time for lignification to take place before the cold set in, resulting in collapsed tissues and death to ends of branches. While these dead areas will eventually fall away, pruning out dead twigs can also be done.

The same weather conditions brought about the white streaks of sap on tree trunks and branches. As spring weather warms the atmosphere, sap flow rises from tree roots, bringing much needed water, nutrients, and stored sugars, distributing throughout the tree. Freezing cold will cause the water in sap to freeze, bursting cell walls and causing cracks in bark. Sap leaks from these wounds, eventually turning white as it drips down the trunk and branches.  Often, secondary infections take place, with Cytospora fungal pathogens entering wounds and expanding damage in water-conducting tissues. In some cases, the top of the tree dies completely.

When the top of a spruce or other conifer dies, the form of the tree can be salvaged by re-establishing a central leader.  The dead leader is cut away and a side branch is gently curved upward and secured to a stake placed along the trunk.  Staking materials must be removed in one year to keep materials from causing further damage to the tree.

There isn’t anything to counter freeze damage and the resulting Cytospora infection.  While tree owners want to help, fertilizing these trees should not be done as this results in deepening tree stress. Practicing good tree care is an excellent step: water deeply during dry spells, mulch with 2-4 inches of wood chips, and refrain from using any herbicides containing dicamba anywhere near trees.   By practicing good tree care, the tree’s own defenses are enabled to weather setbacks.

Rain Barrels

A recent brief rain burst, depositing just .2 of an inch in my rain gauge, put 12 gallons of water in my rain barrel. That’s the beauty of collecting rainwater from a roof—a small amount adds up quickly.

If you’ve been considering installing a rain barrel, here is a push to get you started. While rainwater doesn't carry a lot of dissolved stone like hard water does, using rainwater benefits plants in ways that hard water never can and without the detrimental residual salts associated with water-softened water. Rainwater has trace elements good for plants, has a pH that is slightly acidic (also good for plants), and since it is the same temperature as the outdoors, won’t shock plant roots when watered in.

Capturing rainwater is not a new concept. Our foremothers and forefathers certainly knew of the benefits of catching rainwater. Utilizing roof gutters and downspouts, rainwater was collected in underground cisterns and provided quality water to use in gardens. Today, rain barrels are utilized by many as a way to have access to water where a well and a water line don't exist. One community garden in just this type of situation collects water from a neighbor's roof for the community garden members to use. One happy side benefit of catching rainwater is that it doesn't add to the volume and speed of water that causes erosion.  

Kits can be purchased, providing all the components necessary to set up a rain barrel. If you're pulling together the materials yourself, a used food-grade barrel is an economical start. Set the barrel up on concrete blocks to make access to the spigot easier.  A downspout diverter mounted on the downspout will divert water to the regular downspout when the barrel is full. Choose a spigot that readily fits your garden hose and mount the spigot near the bottom of the barrel. Place screen over any openings at the top of the barrel to exclude egg-laying mosquitoes.

A precautionary note, if raccoons are regular visitors on the roof, rainwater should not be collected as their fecal material can readily transmit diseases to humans.  More information about rain barrels may be found at Backyard Farmer at https://byf.unl.edu/rainbarrels .

Vegetable Gardening 101

The Nebraska Extension Community Environment team has put together and launched a new webpage. “Vegetable Gardening 101”is a how-to for new gardeners desiring to learn more about the challenges and rewards of gardening in Nebraska.

Housed on the Backyard Farmer website, “Vegetable Gardening 101” focuses on:

·selecting what vegetables to grow;

·choosing a good site to grow the garden;

·how to determine what size the garden should be;

·building the garden, whether it is a raised bed or in the ground;

·when to plant based on cool season or warm season vegetables;

·determining whether to directly sow seeds or if transplants are needed to get a jump start;

·understanding plant size so plants aren’t planted too close together;

·identification and prevention of insect, disease and weed problems; and

·the harvest and storage of vegetables with an eye towards food safety.

Each section is designed to give a quick overview for those who want enough information to get started while supporting information is provided for gardeners who want to dig deeper, with links to NebGuides (topic-specific information publications) and Backyard Farmer video segments.

Vegetable Gardening 101 is found at https://go.unl.edu/veggies101 .

Moles and Grubs

It’s been a good year for moles.  A nice amount of rain keeps soils moist and workable—the perfect environment to enable mole movement as they “swim” through the soil. Many people approach the problem of moles by focusing on grubs—that if the grubs are gone, then moles won’t be in the lawn. Though not accurate, it leads to grub control measures that do little to minimize mole activity.    

In studies that examined the contents of mole stomachs, earthworms dominated as the preferred food choice, with ants being a distant second. Those involved with wildlife damage management are aware of this, utilizing toxic baits that replicate earthworms’ odor and taste. Because moles are insectivores, they won’t eat poison peanuts or chewing gum.  

Moles create two different types of runs—a daily use tunnel that gets re-used and then the forage tunnel that is used once and abandoned. The only way to know the difference between the two is to first step down all tunnels.  The ones that are bumped up the next morning are the daily use tunnels. This is where earthworm mole-killer baits or harpoon traps should be placed. A repellant utilizing unrefined castor oil is another option to move moles out of the area.

The immature stage, the grubs, of masked chafer, May/June and Japanese beetles are the main culprits behind insect damage to lawns. As adults, masked chafer and May/June beetles do little in the way of damage to plants. Not true with Japanese beetles, who especially enjoy feeding on roses, linden, birch and grape. Control measures for Japanese beetle grubs as a strategy to minimize damage to landscape plants from adult beetles later simply doesn’t work because beetles fly in from other areas.

For lawns, it’s good practice to focus management tactics when grubs are actively feeding. While we see grubs during spring planting projects, grubs are causing little in the way of feeding damage, instead devoting energy to pupation to then emerge as adult beetles. It is the next generation of grubs where damage to lawns can be extensive because the younger instars (the stages of development) are actively feeding, severing turfgrass roots.   Products containing the active ingredient chlorantraniliprole can be put down on lawns in early July to target grubs while they are small and do not harm pollinators.

Master Gardeners are ready for you calls!

Do you have a Horticulture Question? Master Gardeners will be available to answer your questions on:

  • Mondays, from 9 a.m. to Noon at the Washington County Extension Office (402) 426-9455
  • Wednesdays & Fridays, from 9 a.m. to Noon at the Dodge County Extension Office (402) 727-2775

Straw Foxglove

Unlike foxglove that are biennial, straw foxglove (Digitalis lutea) is a true perennial. The light yellow bell-shaped downward-facing flowers are smaller than their biennial relatives, but what is lost in flower size, straw foxglove makes up for in reliability and ease of growth.

Straw foxglove does best in average garden soil in a site that receives about 2-5 hours of direct sunlight daily.  Planted at the edge of tree lines, in woodlands, or where the neighbor’s garage shades your yard, this foxglove excels in challenging sunlight conditions. Its short stature, at 18-24 inches in height, makes it a good choice for the front of a shady border. Water during dry spells and mulch with a 2-4 inch layer of woodchips to keep soil evenly moist.  Spent flowers may be deadheaded or left in place to allow seeds to fall around the parent plant.

Sources list straw foxglove as a short-lived plant and winter hardy to 5° F. My clump of straw foxglove is 10 years old now, with no attention given to providing protection from winter winds. Maybe this plant hasn’t read the literature because it’s survived a house move, has, at times, competed against taller weeds, and withstands the winters Mother Nature sends its way. After all that, it blooms its head off, producing 18 inch stalks of delightful flowers in late spring and early summer. 

Straw foxglove is pollinated by long tongued bees, like the carder bee.  Both the nectar and pollen are food for pollinators and their offspring. The plant is toxic to mammals, so both deer and rabbits stay away.

Straw foxglove plants can be hard to find. Ask your local nursery or garden center if they can order them in. The seeds of straw foxglove, which is how I started my plants, can be ordered online and through catalogs. 

Trees and Galls

Galls are structures made up of plant tissue, forming in response to the saliva of mites or small insects as they feed. The number and variety of galls found on trees in our landscapes are closely associated with the weather and how conducive it is to gall-producing arthropod populations. Galls happen every year, it’s just some years the number may be higher because that insect population is higher. For the most part, gall formation on leaves is of little concern, while those affecting the twigs, branches and stems merit closer monitoring.

Maple Bladder Gall

Bright green nubs, just 1/8” across, form on the upper surface of silver and red maple trees. The galls turn from green to red, eventually darkening to black. In some years, the galls are so numerous on a leaf that the extra weight causes leaf drop. While the galls look weird, they are actually made up of leaf tissue, with one mite for each gall. The gall serves as the mite’s home and food source.  Once tree owners notice galls, spraying a miticide is ineffective because of the protection the leaf tissue provides to the mite.  Maple trees exhibit no stress from the presence of mites. In fact, galls photosynthesize, providing needed sugars for the tree.

Linden Spindle Gall

Of all the potential problems lindens can have, their tubular-shaped leaf gall is the least of them. Spindle galls are caused by the eriophyid mite. Like the maple bladder gall, the mite’s saliva initiates a response in plants where they increase the size and number of leaf cells, which then grow over and encapsulate the mite.  Since no real harm comes to linden trees from the spindle gall mite, treatment is not necessary.

Willow Pine Cone Gall

The pine cone gall is more of a curiosity than a problem.  Cone-like growths form on the ends of willow twigs. Formation stems from the activity of the gall gnat midge. Masquerading as a pine cone on a willow, the galls are green and scaly, developing fuzziness as they age. Treatment for the gall gnat midge is not necessary. Galls may be removed if tree owners find them offensive or they can be left on the tree to show off their quirkiness.

Ash Flower Gall

The male flowers of white ash are prone to invasion by the ash flower gall mite. Flowers will develop into bright green broccoli-like growths.  These growths eventually age to dry brown clusters that remain in trees until they break away.  The formation of galls prevents the male flowers from producing pollen, which is a good thing if you’re an allergy sufferer or don’t want the female ash flowers being pollinated and producing lots of seed. Even though tree owners find ash flower galls offensive, trees remain healthy and treatment is not necessary to control the ash flower gall mite.

Hackberry Nipple Gall

That hackberry is one tough native tree is undisputed.  Every year, the undersides of leaves display miniature barrel-shaped galls. These galls are formed of plant tissue in response to feeding by psyllids, otherwise known as jumping plant lice. While the number of galls on leaves can be alarming, no harm is caused and treatment is not necessary.

Oak Bullet Gall

Any time galls form on twigs and branches, the potential for long term damage increases. In the case of oak bullet gall, the formation of galls is on the perennial parts of the tree, in this case the twigs and small branches. Bullet galls, the result of feeding by the cynipid wasp, grow primarily on bur and swamp white oak. Initially galls are green, gradually darkening to brown and remaining on the tree long after the adult has emerged.  Older, well-established trees really aren’t harmed by oak bullet galls, but young and newly-planted trees can have branch dieback if there are a large number of galls. Trees that are thriving will have fewer detrimental effects from oak bullet galls.  Hanging feeders near young trees will attract birds ready to eat the non-stinging cynipid wasps. Pruning out heavily infested branches and then burning, burying or chipping them will decrease cynipid wasp numbers.

Weather is a huge factor impacting the number and variety of galls found in our landscapes, mainly because weather affects insect populations. Arborists and horticulturists see galls every year but the number of galls vary from one year to the next. Quite simply, galls and the insects that cause them are a thing of the past with autumn leaf drop.

 

Rhubarb

Rhubarb, Rheum rhabarbarum, is an easy-to-grow perennial that lends a delightfully tart taste to pies, crisps and jams. The fact it is a perennial means there’s no extra labor to grow plants annually from seed like you do for the vegetable garden.  The edible part of rhubarb, the petiole (also called a stalk), is technically not a fruit, but its size relative to fruit trees makes rhubarb a nice fit for a smaller space.  The robust leaves, though poisonous, are eye-pleasing and make an unexpected addition into landscape plantings.

Depending on the variety, the stalks of rhubarb range in color from light green to hints of red to strongly red.  Varieties like ‘Canada Red’ and ‘Crimson Red’ have bright red stalks while ‘Victoria’ has green stalks. Rhubarb performs robustly in a location where it gets sun all day but will still do OK in a location where it gets a minimum of 6 hours of direct sunlight each day.  Crown rot can be a big problem in dense soils, so amend the site liberally with well-rotted manure or compost. Spring is a good time to add rhubarb plants to the garden as well as dividing clumps that have been in place for four or more years.

During its first growing season, none of the stalks of rhubarb should be harvested, allowing time for the crown and roots to establish.  In the second year, a few stalks can be harvested. From the third growing season on, stalks can be harvested starting in May and continue through mid-June. Stalks should never be cut from plants because the stubs left behind are entrance points for pathogens. Instead, firmly grasp each stalk and give a slight twist while pulling.  The stalk will disengage from the crown.

The toxins produced in rhubarb leaves do not transfer into the stalks if leaves wilt. It’s still best, however, to prepare only firm, fresh stalks for baking. As the growing season progresses, rhubarb stalks get progressively tougher and stringier. If a special occasion calls for rhubarb later in the season, a few of the newer stalks can be pulled with no detrimental effects to the health of the plant.

Because rhubarb is a heavy user of soil nutrients, dig and divide plants every fourth year or so, moving plants to new locations and amending the soil with well-rotted manure. Divide plants with a sharp spade to ensure clean, not jagged, edges. Plant the crown even with the surface of the soil. Water plants thoroughly and maintain about an inch of water per week, precipitation and irrigation combined, to foster good growth.  Healthy plants growing in a well-prepared location have few insect and disease problems.  Occasionally, rhubarb sends out flower stalks. These should be clipped away so the plant does not expend energy to develop seed. 

Woodland Phlox

Woodland phlox, Phlox divaricata, also known as wild sweet William, is a shade-loving perennial that produces lavender blue five-petalled flowers in spring.  It has a wonderfully long bloom season. In my garden, it has been sending out flowers for a solid month now.

Woodland phlox does best under trees in soils rich in humus. The plant naturalizes, gradually spreading into empty spaces when stems touching the ground root.  At just 12 inches in height, the spread is not aggressive, knitting in around other shade lovers like hosta and Solomon’s seal. Mulch plants with a 2-4 inch layer of wood chips to keep soil evenly moist and water during extended periods of dryness.

Woodland phlox is an outstanding plant for pollinators, providing pollen and nectar early in the season when food sources can be scarce. While deer don’t read the list of plants they won’t eat, woodland phlox is not a preferred food source for them.

Woodland phlox is readily found at garden centers and through catalog companies. This lovely wildflower is included on the list of pollinator plants found here: http://go.unl.edu/pollinatorhabitat .

 

Warm Season Vegetables

Cool season vegetables are those that grow best during the cooler growing conditions of spring. Warm season vegetables are those that do not survive frost and should be planted after May 10, around Mother’s Day, to ensure no late frost damage.  If planted earlier, plants should be covered if frost is forecasted.   Since warm season vegetables thrive in the heat of summer, there is no advantage to planting early outside when soils are cold as this slows plant vigor.  Is it better to direct seed into the garden or do warm season vegetables do better started indoors? For some, like tomatoes and peppers, plants planted in the garden give a head start, producing earlier, while others it’s easier to direct sow.

Warm Season VegetableDirect Sow SeedsSet Out PlantsComments

Green Bean

 

Pole and bush types.

Corn: Sweet and Popping

 

Bi-color sweet corn is one of the most popular types.

Cucumber

Slicing, pickling, burpless types; use caution when setting out plants as roots break easily.

Eggplant

 

Traditional egg-shaped as well as slender Asian types.

Greens: Malabar spinach, New Zealand spinach, Swiss chard

These greens are heat tolerant. Malabar and New Zealand spinach are not a true spinach but have a flavor similar to spinach.

Melon: Honeydew, Muskmelon, Watermelon

Check the number of days until harvest; use caution when setting out plants as roots break easily.

Okra

 

Harvest when small for tender pods.

Onion

 

Start seeds indoors in January; sets will produce scallion-type early and bulbs later on.

Pepper

 

From sweet to mildly hot to scorching, check the Scoville Index for degree of hotness.

Squash, Summer

 

Numerous types, including zucchini, patty pan, yellow crookneck.

Squash, Winter

 

Butternut, acorn, blue Hubbard, pumpkin.

Sweet Potato

 

Purchase cuttings or start your own.

Tomato

 

Tremendous variety including heirloom, hybrid, cherry, Roma, beefsteak.

Hydroponics Workshop - May 5, 12, 19, 26

With a growing interest in gardening, including interest in small-scale hydroponics, Stacy Adams (extension specialist and associate professor of practice/Agronomy and Horticulture) will be offering a 4-part virtual course for home hydroponics in May.   You can also find and share the Facebook event/post at: https://bit.ly/2KxfU2o

The course is Tuesday evenings 6pm – 7:30pm CDT, cost is $25. 

Registration link: https://cvent.me/kMZM2o

Putting “Earth” in Earth Day

The first Earth Day was celebrated in 1970 to celebrate all things plant, water, and air. What’s not celebrated is that unsung hero—earth—not in reference to our planet, but earth, the stuff we plant in.  Otherwise known as soil, dirt, land, and loam, earth supports most plant life on planet Earth. Yet earth is little appreciated and vastly underrated. David R. Montgomery, author of Dirt: The Erosion of Civilization, tells us “Societies that don’t take care of their land don’t last.”  In his book, Montgomery documents time and again civilizations no longer able to feed themselves because of loss of soil fertility and erosion.

Gardeners the world over know when they’ve got challenging soil conditions.  Words like “muck,” “hardpan,” and “gumbo” are some things said about less-than-ideal soils. Removing topsoil during construction; soil erosion from grade changes and loss of protective vegetation; cultivating soil to a powder-like consistency; bagging grass clippings instead of mulching them in; and adding things that don’t belong there (like landscaping fabric, excess fertilizer, and petroleum products) are just some of the ways our current practices destroy the recuperative potential of soil.

Additions of organic matter, whether its grass clippings, composted kitchen scraps or well-aged manure, add to the carbon content of soils, making them darker in appearance and providing a necessary component of plant photosynthesis. Organic matter loosens dense clay soils and increases water-holding capacity of sandy soils. Water droplets—from irrigation and rainfall—damage unprotected soils by loosening soil structure, leading to erosion. Mulches and plants protect soils from the damaging effects of water droplets.

Think destructive practices only hurt soils and nothing else? Not so. Soil is a substrate, supporting plant roots and thus stabilizing plants. Soil is one of the most diverse biomes on earth, with beneficial macroorganisms like sowbugs and millipedes and beneficial microorganisms like bacteria and fungi, breaking down organic matter and thus making nutrients readily available to plants. Just one teaspoon of soil contains thousands of living creatures and the more diversity in our soils, the greater the diversity of life supported above it.

The earth under our feet isn’t glamorous and doesn’t grab headlines. It is, however, essential to life and worthy of our time and attention to take care of it, not just on Earth Day, but all days.

Chives

Of all the herbs in my herb garden, chives are the earliest to send out their slender stems in spring. So even when the vegetable garden isn’t producing yet, I can add something fresh to the food I’m preparing by heading outside to snip some chives. They add a nice mildly onion-y taste to salads and they look great on baked potatoes. This perennial plant is not only easy to grow but its frost resistance makes it a colorful contribution to the table from early spring until late in the fall.

Chives are easy to grow from seed in the spring.  Prepare a seed bed and gently press seeds into the soil.  Cover seeds lightly with soil and moisten them with a gentle sprinkle of water.  Mark the spot and in about 14-28 days, you’ll see tiny slender stalks emerging from the soil.  Keep the seedlings evenly moist as they grow.  If started indoors, plants should be hardened off (acclimated) before planting them in their permanent place.  If started outdoors, be sure to choose a location that gets more than 6 hours of direct uninterrupted sunlight daily.

Chive plants can also be readily found in nurseries and garden centers. When planted, they’ll appreciate a location with lots of sunlight and a soil high in organic matter. Keep plants watered during dry spells to keep them producing. More plants can be obtained by dividing existing plants.  Once clumps get larger than 10 inches across, division is a good idea to keep plants healthy and producing lots of tender stems.

A quick word about chives and garlic chives. Both require similar growing conditions and are quite tasty, but, left to their own devices, garlic chives are thugs and can be RAMPANT in the garden. Both regular chives and garlic chives have flowers, but where the two types differ is that while regular chives may have a few seedling volunteers around the parent plant, garlic chives will have a massive number of seedlings.  Herbicides do little in the way of controlling the unwanted progeny, so clipping and removing flowers is the easiest way to keep garlic chives from dominating the herb garden. Thankfully, the flowers of both chives and garlic chives are a wonderful edible garnish for salads and sandwiches. The flowers benefit our pollinator friends too.

More information about growing herbs can be found here:  https://grobigred.com/2017/05/19/growing-requirements-for-selected-culinary-herbs/ .

The Northern Pecan

In preparation for April 14’s National Pecan Day, what better way to celebrate the day than planting your very own northern pecan tree, Carya illinoinensis. Native to southern Wisconsin and the northern parts of Illinois and Iowa and extending south to Texas, the northern pecan can handle winter temperatures as low as -35 degrees F.  It has pinnately compound leaves that turn a beautiful yellow color in the fall. This tree gets large, upwards of 70 feet, with a crown extending 40 feet or more, so give it plenty of room at planting time. 

The northern pecan tree is monoecious, meaning it has both female and male flowers on the same tree. The best nut production, however, is ensured when more than one pecan variety is planted. The nuts mature around mid-October and are highly nutritious. From planting, northern pecan trees can start producing in as little as 6 years.

The northern pecan is not fussy as to soil pH, being tolerant of alkaline as well as acidic soils.  They do, however, need to be in a well-draining soil to prevent crown and root problems. The extensive tap root that the northern pecan develops makes it highly drought tolerant but it also limits recommendations for a starter-sized tree. People seeking the best results for nut production from their northern pecans should start with small trees, those started in 4-inch pots are ideal. A small tree isn’t an impediment—the idea is to get it planted before a deep tap root has developed. Since the northern pecan has such a wide native range, purchasing a tree from a nursery that collects seeds from the northern parts of its range will be important to assure winter hardiness. Once happily planted, the northern pecan doesn’t waste any time when it comes to growing, increasing in height more than 12 inches each growing season.

If you’re interested in knowing more about growing the northern pecan, or any type of nut tree suitable for this area, check out the Nebraska Nut Growers Association at nebraskanutgrowers.org and the Northern Nut Growers Association at nutgrowing.org.

Garden Update for week of March 23, 2020

Garden Bits - By Kathleen Cue, Nebraska Extension Horticulture Educator in Dodge County

If you’re at home and practicing social distancing, the one bit of good news in all of this is that we can be outside to tinker with plants. Spring is an exciting time, full of promise and possibilities.  If you’re not a gardener, no worries, learning how to garden is a trial and error process. The definition of a gardener, after all, is “one who kills many plants.” Heaven knows I’ve killed my share and I’ve learned far more from my failures than my successes. Even now, umpteen years of gardening and two horticulture degrees later, I still relish the challenge of growing a vegetable I haven’t grown before, planting a tree I’ve only seen in catalogs, and searching for that elusive new cultivar I’ve heard about.

Now is a great time to plant the seeds of cool season crops like radishes, lettuce, and snap peas into the garden.  Broccoli, cauliflower, and cabbage transplants can be set out too. Tomato and eggplant seeds can be started indoors for moving plants outside after danger of frost is past.  If fresh herbs are your thing, start basil, dill, parsley and cilantro inside, planting them outside after frost. Whatever kind of edible gardening you like, new as well as veteran gardeners can add something different each year. What new favorites are just waiting for you to try them?

‘Montmorency’ and ‘North Star’ are two sour cherry cultivars that have been around for a long time. Now, new releases of shrub-form cherries offer cold tolerance, shorter stature, AND high sugar content. From the University of Saskatchewan comes the Romance Series of cherries, with cultivar names like ‘Romeo’, ‘Juliet’, ‘Cupid’, ‘Crimson Passion’ and ‘Valentine’.  These tough cherry shrubs are new enough to the green industry that finding them can be problematic. This doesn’t mean they are impossible to find but ordering early is important.

Extension Master Gardeners are gearing up for Growing Together Nebraska, a joint service program between Nebraska Extension’s Nutrition Education Program and Master Gardeners to grow vegetables for the food insecure.  Even if you don’t have a Growing Together Nebraska program in your county, be sure to donate excess produce from your garden to local food pantries. 

It’s March!

Master Gardener Program Update

Nebraska Extension Master Gardener volunteers are awesome.  Not only are they the boots on the ground to provide gardening information to others but they engage with members of their communities to make their towns and counties better places to live.  They provide gardening expertise and advice to community, school and child-care gardens and they maintain a sharp look-out for problems that can be solved with plants, like fostering insect pollinator health, remediating soil erosion, providing best tree management practices and instilling vegetable gardening skills for the food insecure. Master Gardeners do this through “Ask the Master Gardener” tables, at educational gardens, programs to civic groups and schools and via the horticulture helpline through Nebraska Extension county offices.

The Panicle Hydrangea

The panicle hydrangea (Hydrangea paniculata) gets its name from the huge pyramidal-shaped white flowers it produces. This shrub, introduced to this continent in 1862, originates from China and Japan and easily withstands the winters that the Midwest can throw its way. Unlike the finicky blue-flowered types (Hydrangea macrophylla), the panicle hydrangeas produce show-stopping flowers reliably, even after the worst winter. It is hardy to USDA zones 3 through 8.

Panicle hydrangea does best in sun to part-shade locations although it appreciates some protection from afternoon sun.  Soil pH is not a concern, as long as it has a good amount of organic matter and drains well. Water during dry spells with one inch of water, applied all in one application, per week.

Older varieties like ‘Grandiflora’ (the PeeGee hydrangea) and ‘Tardiva’ have been around for quite some time, but development of new varieties by plant breeders Pieter Zwijnenburg Jr., Tim Wood, Johan Van Huylenbroeck, and Jean Renault has brought fresh enthusiasm for the panicle hydrangea:

▪Limelight™ boasts white flowers with lime-green sepals.  At 8 feet tall and wide, this is a big shrub. 

▪For smaller yards, Little Lime® is just 5 feet high and wide and flowers develop tones of pink as they age.

▪BoBo® is almost completely covered in large rounded panicles of white flowers when in bloom. At just 3 feet tall and 4 feet wide, the strong stems are up to the task of keeping the flowers out of the dirt.

▪Pinky Winky® develops 12 inch long panicles of white flowers that mature to pink. It is 6 feet tall and wide. 

▪Quick Fire® is the earliest to bloom of the panicle hydrangeas. This 6 foot tall by 8 foot wide shrub has white flowers that gradually change to pink and then dark pink.

▪Little Quick Fire® has similar flower traits as Quick Fire® but with a smaller stature at 5 feet tall and wide. 

▪What sets Firelight® apart from other panicle hydrangea varieties is the white flowers that age to vivid red.  At 8 feet tall and wide, this is another large shrub.

▪Zinfin Doll® develops white flowers that change to pink and then dark pink at maturity. It is 6 feet tall and wide.

Gardening Projects

What really sets Nebraska Extension Master Gardeners apart from garden clubs is their dedication to learning Best Management Practices, the cornerstone of what the land grant university has to offer, whether it is an invasive insect, a tough weed to manage, or a proven plant variety to try. This dedication to learning shows in the enthusiasm Master Gardeners share with Nebraskans through direct education (the helpline and tabling events), growing food for the food insecure, and managing education gardens.

Plant a Row for the Hungry began in 1995 by the Garden Writers Association. This program and other programs like it encourage gardeners to grow an extra row of vegetables and donate them to local soup kitchens and food pantries. While nonperishables are the backbone of donations to food pantries, fresh vegetables and fruits can be in short supply. It doesn’t take much extra effort and Individual gardeners or groups can participate. For possible locations of fruit and vegetable donations, contact your local Extension Office. A really heartwarming story involves a community garden that collected all the leftover seedlings and seed packets from their gardeners, planting them in the neglected place between the sidewalk and street. The abundance of produce that came from this out-of-the-way spot were donated next door, to the low-income seniors. It was a boon to both the gardeners and the seniors because the senior citizens got fresh vegetables and the gardeners had the careful eye of the retirees keeping watch over their garden!

The Nebraska Certified Pollinator Habitat program sets criteria for residential gardens, municipal landscapes, school gardens, and businesses to have their spaces certified as pollinator friendly.  The plight of honey bees and monarch butterflies is well-known but the unsung heroes, native bees, are virtually unknown.  This is sad because they are real workhorses—just 250 native bees do the pollination work of 30,000 honey bees. A diversity of flowering plants, a water source, and places of shelter are what’s needed to help native bees and other pollinators.  More information and an application may be found at: http://go.unl.edu/pollinatorhabitat.

“Prune when the saw is sharp” is an old adage whose time has passed.  New research indicates trees and shrubs are best pruned in April, May or June, months that show the best turnaround time for wound closure. Why is it important for wounds to close on a timely basis you ask?  The longer it takes for trees and shrubs to form callus tissue over wounds means the likelihood from fungal and bacterial infections increases. Oak and elm are the exception to pruning in April, May or June because certain insect-vectored diseases are prevalent then.  Oak and elm are pruned during the dormant season, November through February, when freezing weather means insects are not active. 

February’s Garden Basket

February, March and April are busy months for the Nebraska Extension Master Gardener program.  Master Gardener Interns are participating in classes, on their way to becoming certified Master Gardeners.  The classes are intensive, covering botany, plant diseases, landscape design, bug boot camp, and plant management.  Once coursework is complete, Master Gardener volunteers hit the ground running, providing expertise to community and child care gardens, answering questions via the horticulture helpline and “Ask the Master Gardener” tables, and caring for plants at educational gardens.

February is also a busy seed starting month.  Gardeners striving to have greater variety in their vegetable and flower choices than ready-grown 4-packs offer are prepping soil, cleaning seed flats and reading seed packets. Peppers are one of those plants that really benefit from starting seeds early. As seedlings, plant growth is slow to develop, so to have blooming-sized plants to set out in May, starting early is essential. 

February is a good month to think about landscaping tasks during the coming year.  February falls under the planning phase of “plan, plan, plant”, which prevents overplanting, overspending, and overextending labor resources for hastily made plans. Most homeowners can execute wonderful landscapes in their own yard, after all, they know their site best.  While they may lack a plantswoman’s knowledge of the array of plants suitable for their zone, a call to the local Extension office or garden center can remedy that. There, the question can be asked “I’m looking for a small tree (or ornamental grass, or large tree) for this spot in my landscape, can you provide some recommendations?”

February can be an exciting opportunity to look at new plant introductions: 

▪All America Selection (all-americaselections.org) winners are chosen from trials across the country.  For 2020, check out ‘Snak Hero’ pea, ‘Galahad’ tomato, ‘Holi Pink’ zinnia, and a host of other AAS flower and vegetable winners.

▪“Great Plants for the Great Plains” (plantnebraska.org) is a cooperative program between the Nebraska Statewide Arboretum and Nebraska growers with introductions and plant releases of trees, shrubs and perennials well suited to Nebraska conditions.  

▪The Perennial Plant Association has named ‘Sun King’ Japanese spikenard (Aralia cordata ‘Sun King’) as the 2020 Perennial Plant of the Year.  This bold (4 feet high and wide) shade-loving perennial boasts golden yellow foliage, brightening shady and part-shade areas of the yard.

No matter the skill level, February’s array of garden basket possibilities can whet gardeners’ appetites for the season ahead!

Master Gardener Informational Meeting

If you like to garden and are interested in helping people, the Nebraska Extension Master Gardener Volunteer program may be a good fit for you.  People can find out more at the Master Gardener informational meeting Tuesday, January 7 at 3:30 pm at the Dodge County Extension Office, 1206 West 23rd Street in Fremont. You don’t have to a Dodge County resident to participate. The education is available to surrounding counties as well.

Participants will have the opportunity to learn about the class work and volunteer activities of the program, as well as ways Master Gardeners improve the lives of residents of their communities and state. No preregistration is necessary, participants will sign in at the door.  Applications to the Master Gardener program are only available at this meeting.

Master Gardener classes cover important topics like Integrated Pest Management, diseases of fruit trees, proper tree planting and pruning, insect pests, and a host of others, all designed to lay the groundwork for Master Gardener Volunteers to have the necessary skills to grow healthy plants and foster a green environment. All classes are taught by UNL faculty and Extension staff.

Questions?  Contact Kathleen Cue at 402.727.2775 or email at kcue2@unl.edu.  See you there!

Information on this flyer.

The Amaryllis

Of all the holiday plants, the amaryllis boasts some of the largest flowers and can be one of the easiest to grow for next year’s re-bloom. Bulbs received as gifts can be planted right away and their fast growth will amaze everyone, even those with brown thumbs. Hybridization has greatly expanded the red-flowered offerings of the amaryllis, with flowers of pink, white, salmon, fuchsia, the softest of yellows, striped, narrow-petalled, double blooms or miniature. Any way they are enjoyed, amaryllis can be an exciting gift for novice gardeners as well as the skilled.

Bulbs are graded according to size, with premium-sized ones sending out two or more flowering stalks.  If the bulb doesn’t come with a pot, no worries, just choose a pot that is two inches larger in diameter than the bulb.  This allows about one inch of soil space completely around the planted bulb.  Add soil so the soil line comes half way up the side of the bulb.  Water and place the potted bulb in a bright window. Once leaves and flower stalks emerge, growth is amazingly quick.  Growth is so quick, in fact, that staking may be necessary.  Give the pot a quarter turn daily to prevent excessive lean toward windows. Remove spent blooms to keep the plant looking good.

Once the amaryllis has completed blooming, remove the spent flower stalk as close to the bulb as possible without damaging leaves. Keep the plant in a bright window and water when dry. The long strap-like leaves will continue to flourish during the winter months. In the spring, after all danger of frost is past, the amaryllis can be brought outdoors, leaving the bulb in the pot or planted directly into the garden.  Water during dry spells and fertilize monthly to help the bulb replenish its carbohydrate storage. Unfortunately, the amaryllis is not hardy in our climate, so be sure to bring in the bulb in the fall before the first frost.  The bulb will need about nine weeks of rest before it will flower again so store it in a cool (not freezing) dark place. To initiate flowering, place the potted bulb in a bright window and resume watering.

Amaryllis bulbs taken care of in this way will continue to provide flowers for years to come.

Pruning Hydrangeas

In the realm of gardening questions, answering “When can I prune my hydrangea?” can be the most complicated.  This is because of the number of hydrangea types that grow in this region, requiring an understanding on our part before the pruning saw is even employed.

It’s important to note that pruning most woody plants in April, May or June is best in order to minimize wound closure time and maintain plant health. While this may be the ideal time from a plant health perspective, it may mean not pruning at all is key to having reliable blooms.  This is where an understanding of whether the plant blooms on new (current season’s growth) or old wood (stems that developed last year) makes all the difference in having flowers or not.

Smooth Hydrangea

Hydrangea arborescens, sometimes called smooth hydrangea or snowball hydrangea, produces white flowers on current season’s wood.  So no matter how hard the winter or how severe the pruning (in April, May or June), the smooth hydrangea will still reliably flower.  This old-fashioned favorite has well-known newer introductions such as ‘Annabelle’ and Incrediball™. 

Panicle Hydrangea

Hydrangea paniculata is a large shrub that produces huge panicles of white to blush-pink flowers.  Well-known varieties include Limelight®, PeeGee, ‘Tardiva’, ‘Burgundy Lace’, and ‘PeeWee’. Flower buds are reliably winter hardy.  Pruning beyond removal of dead stems, rubbing branches and spent blooms is really not necessary but can be done in April, May or June.

Bigleaf Hydrangea

Hydrangea macrophylla is the most problematic because of hardiness issues in our area.  It produces pink flowers (or blue flowers if aluminum sulfate is added to the soil), primarily on old wood. Rough winters and hard pruning destroy flowering wood, affecting bigleaf hydrangea’s ability to flower. Varieties that belong to this group include ‘Nikko Blue’, ‘Pia’, and Endless Summer®. Blooms can occur on both new and old wood of the Endless Summer® series, which lends some resiliency to flowering after winter dieback or severe pruning means loss of last year’s wood.  But be aware that hot dry periods during the growing season will affect Endless Summer’s ability to bloom on new wood too. It’s best to site all bigleaf hydrangeas where they’re protected from winter winds and, except for dead wood removal, refrain from pruning them altogether (and hope for the best).

Oakleaf Hydrangea

Hydrangea quercifolia produces creamy white flowers and oak-shaped leaves.  While resources state flower buds are killed when winter temperatures drop below -10° F, I’ve observed the one in my yard consistently flowering, even when the winter has thrown -25° winds at it.  Pruning the oakleaf hydrangea involves removal of dead twigs, spent flowers, and rubbing branches, and really nothing more. ‘Alice’ and ‘Snow Queen’ are two well-known varieties of the oakleaf hydrangea.

Looking Ahead: Plan to Help Pollinators Next Year

Kicking back to consider next year’s garden, let benefitting pollinators be one of your considerations.  Of course pollination is important to us because we like to eat—one-third of our food supply exists because pollinators pollinate.  Pollinators, specifically native bees, are real work horses of the pollination world—just 250 native bees do the work of thousands of honey bees.

Some native bees, like the bumble bee, colonize, meaning they hang out together in a social structure with everybody having a specific job to do.  The vast majority of native bees, however, are solitary, living out their lives with no honey to make or designated job to complete.  Why is this important, you ask?  Because improving the environment of a solitary bee involves different strategies than those for hive bees where intervening efforts are concentrated. This doesn’t mean there’s nothing to do to help native bees, quite the contrary.

Plant native flowering plants.  Not only are these plants tough for a reason, the flowers provide a protein source—pollen—and a sugar source—nectar—for developing larvae and adults. Because it’s important to have food sources available in spring, summer and fall, select plants for the time they are in flower.  Group same plants together to better attract pollinators.

Choose to leave a few weeds.  Clover and dandelions are excellent food sources for pollinators. This doesn’t mean the entire yard has to be covered in weeds but a pollinator-friendly yard can be strategic by leaving some weeds in designated areas.

Rocks and pebbles are important in a watering dish. Pollinators will drink from bird baths but be sure to prevent them from drowning by placing rocks and pebbles for insects to alight while getting water. Change out the water every other day to keep mosquito populations down.

Put in a pollinator hotel. This provides cavity-nesting native bees with a place to lay eggs and provision their young with a pollen-nectar combination. Different diameter holes, along with specific depths of holes, will attract different bees.  Find out how to build a pollinator hotel with this NebGuide:  http://extensionpublications.unl.edu/assets/pdf/g2256.pdf .

Use pesticides—herbicides, insecticides and fungicides—sparingly or not at all.  These products have the capability of killing pollinators or, for those that survive, causing erratic behavior, such as disorientation, failure to mate, and not eating.

Apply to have your garden certified as pollinator habitat through the Nebraska Pollinator Habitat program: https://entomology.unl.edu/pollinator/pollinatorapp.pdf .  Remember that any size garden, small to big, benefits pollinators.

Purple Beautyberry

As flowering plants give way to autumn, it’s the fruit that many produce that add interest to our landscapes.  It’s hard to beat the berries produced by purple beautyberry, Callicarpa dichotoma. At a time of the year when fruits highlight the reds, yellows and golds of autumn, it’s nice to see the show-stopping lustrous purple-violet fruits of beautyberry.  The fruits are small, just 1/8 of an inch across, but the numerous clusters along the stem make it a standout. 

Beautyberry should not be confused with beautybush, which is an entirely different plant with a whole other set of flowering and fruiting characteristics.

Purple beautyberry is a shrub, reaching just 36 inches or so in height.  The plant is wider than it is tall, easily spreading to 42 inches across. In our climate, beautyberry acts more like a sub-shrub, meaning the crown and larger branches survive the winter but the twigs and smaller branches do not.  No worries! Even if your beautyberry does not have any winter dieback, cutting back stems to 8 inches in the spring gives rise to more of the small pink flowers (and hence more purple-violet fruits). This hard pruning also results in more compact, less rangy plants.

Sources list purple beautyberry as hardy to USDA Zones 5-8, but I’ve been growing it in my Zone 4 garden for years now and it keeps looking better every year.  The literature lists best fruit production when two or more are planted, providing pollen for one another. This is also debatable, since my lone shrub produces LOTS of fruits every year. The fruit show lasts September through October and provides food for many songbirds.

Plant purple beautyberry in a loamy soil with good drainage. A location that receives 3-6 hours of sunlight daily means that beautyberry can be planted in those challenging locations that don’t receive direct sunlight all day.  Water during dry spells as the plant will drop fruits during prolonged dry weather. Purple beautyberry’s smaller form makes it a great addition to perennial gardens and front entrance plantings.

Give purple beautyberry a try for its showy display of fall fruits.

Growing Garlic

If you’ve grown garlic before, you know that the cloves for planting are found readily in the spring.  What many do not know is that fall planted garlic produces larger cloves than spring-planted ones.  Using this opportunity to plant now means it’s not too late to reap the benefits of fall-planted garlic.

In selecting a site to grow garlic, choose one that gets 6 or more hours of direct uninterrupted sunlight daily and has a well-draining soil.  In dense soils, garlic can rot, so amending the soil with compost first ensures a good crop. Garlic needs a nutrient-rich soil, so sandy soils will also benefit from the addition of compost.

In selecting a garlic variety, be aware there are hardneck and softneck types. Hardneck varieties store best over the winter months while the softneck types, favored for braiding together, have a short shelf life.  Garlic from the grocery store has been treated to inhibit sprouting, so it isn’t a good choice for planting. For the upper Midwest, choose hardneck varieties for their hardiness. Flavors range from mild to buttery to fiery.  There are heirloom types, such as ‘German Red’ and ‘Georgian Fire’, as well as newer types, like ‘Korean Red Hardneck’ and ‘Great Lakes’.  Whatever variety you choose, growing your own garlic is easy and opens up a world of culinary possibilities.

Each garlic clove produces one head of garlic.  The larger the clove planted, the larger the head of garlic produced.  Separate the cloves from the bulb when you’re ready to plant.  The flat basal plate goes to the bottom of the hole, with the point facing skyward.  Holes should be 3-4 inches deep and spaced about 6 inches apart. The first thing the clove does is put down roots to maintain moisture levels.  In some instances, there may be green growth sprouting from cloves but this greenery should not be cut off, instead leaving it to nourish plants. 

In the spring, growth in earnest begins, sometimes with the plant sending up a seed stalk. The seed stalk should be snapped off to encourage the plant to put energy into growing a larger head of garlic.  The seed stalk is edible if harvested when tender, so don’t be afraid to use it in dishes where a garlic flavor is desired. Garlic does best when plants receive about 1 inch of water per week. Bulbs are ready to harvest when the foliage dies back by about one-half.  The biggest garlic bulb can be saved back for planting garlic cloves in the fall, starting the process again.

Now that you know fall-planted garlic is easy to grow and yields great results, the next thing to do is to get out those gardening gloves!

The Brown Marmorated Stink Bug

The brown marmorated stink bug is a nuisance as well as a destructive pest and, like its name implies, puts off a nasty odor when crushed. This nonnative invasive pest has been in Nebraska since 2012. The damage the BMSB causes is from its needle-like mouthpart that punctures, resulting in sunken bruised areas on fruits. It feeds on a wide range of crops, including soybeans, corn, apple, pear, peach, cherry, peppers, tomato, maple, redbud and serviceberry, to name a few.

The BMSB is characterized by bands of white on dark antennae and white inverted V-shapes along the edge of their body. The insect itself is shaped like a shield and is about ½ inch long.

Like the Asian ladybug, the BMSB seeks winter shelter beneath house siding and structures that have openings that allow access. Once in walls, they can easily make their way inside the house where they become a nuisance, especially when their population numbers are high. Fortunately, they do not bite or spread diseases to humans, although in rare occasions their odor can cause an allergic reaction. 

BMSB can be hard to manage, in particular as they seek overwintering sites.  Spraying the foundation and siding with a home perimeter spray helps to keep the insect from gaining access inside.  Indoors, utilize a shop vacuum, putting 1-2 inches of soapy water into the tank so that bugs drown.  You can use a regular vacuum cleaner to clean up BMSB but be aware that their odor may transfer to the machine itself. Insecticides and foggers are not recommended to manage BMSB populations indoors. Check around windows, doors, chimneys and air conditioners for a tight fit and use silicone caulk and weather-stripping to close gaps.

To find out more about the brown marmorated stink bug and the crops it can damage, go to: http://www.stopbmsb.org/managing-bmsb/ .

Weed Musings

In the midst of September, if weed management isn’t on your autumn to-do list, it definitely should be. Fall is the best time to be applying herbicides to perennial weeds. Why is this so? As plants ready for winter, sugars produced in leaves are transported to the roots for storage.  With herbicide applications, the plant’s internal transport allows herbicides to move readily from leaves to roots, providing for excellent distribution and better control.

Recognizing something as a weed is not enough. Identification is critical to making sure your time, labor and resources are used to good effect. Crabgrass and foxtail, the bane of many lawns and gardens, are annual plants and will die with the first hard freeze. So using herbicides on annual plants in the fall doesn’t make a lot of sense.  Dandelion, ground ivy, brome grass, and poison ivy, however, are perennial plants and management efforts will be more effective now.  Plan to get at least two applications of the herbicide down before the first hard freeze, spacing the timing of the applications according to the label directions.  If you need help with identifying the weeds in your garden and landscape, the Nebraska Department of Agriculture has an excellent reference, Weeds of the Great Plains.  Information for purchase of this book may be found here: https://nda.nebraska.gov/forms/nw11.pdf .

It’s surprising how the presence of the word “weed” in a plant name brings others to the conclusion that the plant should be removed... immediately.  So if you have Joe Pye weed, butterfly milkweed, or ironweed, this doesn’t mean you should reach for the herbicide.  These are beautiful plants in their own right and benefit pollinators to boot.  While a pristine lawn may be considered the ideal, gardeners can choose to leave some weeds in out-of-the-way places to provide food for pollinators.

Sometimes the word “weed” in a plant name is justifiable, like ragweed, which causes a lot of problems for allergy sufferers. Clients once inquired about the “interesting” plant that appeared on their property.  The plant was none other than giant ragweed and the clients thought the ragweed’s growth rate was so amazing they decided to keep it!  This proves once again that beauty is ultimately in the eye of the beholder.

The Benefits of Fall Planting

The first and most important thing to know is that Fall IS for planting!  Warm soils, cooler temperatures and less weed pressure make it a perfect time to plant regardless if you’re planting trees, shrubs, perennials or Kentucky bluegrass. 

I’m often asked if this is really true. After all, isn’t the best time to plant trees, shrubs, perennials and Kentucky bluegrass is in the spring? Actually no, Fall is better.  Summer’s lingering warm soils coupled with cooler ambient temperatures are perfect, allowing plants to keep needed moisture and establish roots at the same time.  Good roots are important to winter survival and good root growth is achieved before the soil freezes in late November.

Weed seed germination is far greater in the Spring than in the Fall, so doing less cultivating to keep the weeds down means less competition for the desired plants and less work for you.

Finally, don’t miss out on the terrific sales.  If you have a bare spot in your landscape, there’s no need to wait.  Local garden centers have some wonderful sales and promotions going on, often at a significant savings compared to their Spring prices.

http://byf.unl.edu/september-garden-activities

Mosaic Virus on Squash

Viruses represent some of the toughest diseases to manage in cucumber, squash, pumpkin, and melon plants.  Often the disease doesn’t kill but does reduce the size and number of leaves, which in turn decreases fruit production. Cucumber mosaic, cucumber green mottle mosaic, watermelon mosaic, zucchini yellow mosaic, and squash mosaic are some of the viruses that infect plants in the Cucurbit family. The viruses are spread from infected seeds, by aphid feeding, and by mechanical means, such as using a gardening tool on an infected plant and then using the same unclean tool on a healthy one.

When gardeners notice mottled leaves, raised dark green blisters on fruits, and stems that dry out rapidly, a mosaic virus is the likely cause. There is no product to spray that will eradicate the virus from plants. Instead, use certified virus-free seeds, choose varieties that are resistant to mosaic, clean gardening tools with a 10% bleach solution between uses, and remove weeds from inside and outside the garden to reduce the amount of pathogen spread by insects. If you don’t already, clean up the garden this fall to remove vines that can harbor the virus.

Are squash and melons affected by mosaic virus safe to eat?  “Yes,” says Nebraska Food Safety Educator Carol Larvick, citing information from Minnesota Extension. “These viruses are specific to plants and do not harm humans. The presence of mosaic won’t cause fruits to rot prematurely but severely distorted fruit will have a different texture, so use your own judgement.”

 For more information on mosaic virus, check out this website: https://blog-yard-garden-news.extension.umn.edu/2018/09/can-i-eat-that-strange-looking-squash.html .

Landscape Journaling

Landscape journaling, the art and science of keeping track of plants and gardens in the landscape, may seem like a fluffy idea, but the task has merit. Are you having your ash trees treated every other year to prevent an infestation of emerald ash borer? A landscape journal can be a record of when and who treated the tree, along with the timing for the next treatment. Did a new pepper variety perform extremely well in your vegetable garden this year? This can be recorded in a landscape journal to serve as a reminder for next year.

More than once I’ve witnessed a tree service using lag bolts to stabilize a tree split. Successive years of ring growth over the lag bolts made them invisible to those unaware of past repairs. A concern here is that years later someone using a chain saw will encounter this metal—with scary consequences. Not only is a landscape journal an interesting bit of reading to look back on past  tree repairs, I would go so far as to say it should be included with the abstract of the property as a history of what has been done and to prevent injury to others unknowing of past tree work.

Since staking materials should be left on newly planted trees for one year and one year only, a landscape journal is a good place to record when those materials need to be removed next year. Re-training the central leader in your spruce tree after the top died out?  Put this down in the landscape journal as a reminder to remove the staking materials after one year and to track progress as the tree recovers.

Keeping a landscape journal helps us to track what happens when. I can’t tell you the number of times a tree owner will bring in a sample for diagnosis, claiming “It just happened!” when it is apparent the problem has been ongoing for years. With a set of eyes looking at plants, monitoring for problems and recording what is seen, problems are discovered—and treated—sooner rather than later.

A landscape journal can be a place to keep your plant wish list, to serve as a reminder of a monumental failure, to log vegetable crop rotations, and to stash pictures of landscapes you’d like to emulate. Weather events, a large factor in plant stress, can be recorded in a journal, providing that “ah hah” moment, connecting a cause with an effect, sometimes several years later.

Regardless if your garden journal is a hard copy or an electronic record, the information contained within will be invaluable.

 

Helen’s Flower

Helen’s flower, Helenium autumnale, is a native perennial of the sunflower family, producing show-stopping 2-inch flowers in colors of yellow, gold, orange, red or variations in between.  The notched petals, surrounding a yellowish brown globular cone, are a nice touch, giving the flowers the appearance of a ruffled skirt. The specific epithet “autumnale” refers to Helen’s flower blooms in late summer/early autumn, a perfect time when pollinator populations are really booming. Helen’s flower is also known by the unflattering moniker of “sneezeweed” which harkens back to when flower petals and leaves were dried for snuff.

Helen’s flower, along with its cultivars, are hardy to USDA Zones 3-9.  Helen’s flower is not a long-lived perennial, often lasting 4-5 years before it quietly disappears.  This trait shouldn’t sway you from growing Helen’s flower because, besides its ability to re-seed, the plant is a good food source for pollinators, displaying the greatest diversity of pollinators than any other native wildflower in University of Nebraska research.

An interesting and identifying feature of Helen’s flower is the winged stem. Thankfully, the foliage of Helen’s flower does not attract grazing from deer and rabbits. Plants are not prone to disease.

The cultivars of Helen’s flower include ‘Rotgold’ and ‘Rubinzwerg’, both readily found at garden centers and nurseries. ‘Rotgold’ has flowers of red and gold on plants three feet tall with an equal spread, making it a welcome addition to the back of the border. ‘Rubinzwerg’ is shorter, producing rusty red flowers on plants that are just two feet tall and wide.

‘Salsa’ is a new cultivar of Helen’s flower, sporting bright red flowers on plants 20 inches tall and having a similar spread. ‘Mardi Gras’ has red-orange flowers on robust 36 inch tall plants. Among the newest of the new is the Mariachi™ series, sporting bicolor flowers on 20 inch tall plants.

Although native, Helen’s flower does not appreciate dry soils, instead preferring soils that are evenly moist to downright wet, making this a good plant for rain gardens and heavy clay soils.  Helen’s flower also likes a location receiving 4 or more hours of direct sunlight daily.  In dry soil, plants will not thrive and will have a ragged appearance.  Conversely, Helen’s flower grown in a moist area will benefit from staking to hold the plant upright.

Altogether a colorful addition to the garden, consider planting Helen’s flower for the added benefit of nectar and pollen for pollinators!

 

Flowering Plants for the August Garden

When it comes to August’s garden, many gardeners, plant enthusiasts and landscapers are willing to skip the month entirely because of the seemingly few plants that provide interest during August. I’d like to challenge that notion, mainly because August is a perfectly fine month of frost-free weather and why not make good use of it? Whether your goal is to spruce up a drab corner or benefit pollinators, look to some lesser-known flowering plants to brighten your August garden.

Native plants are excellent contributors to the August garden.  The spiked gayfeather, Liatris spicata, is found in many gardens but this genus has way more to offer.  Liatris microcephala, tiny-headed liatris, packs the purple flowers onto stems just 18 inches tall. Liatris pycnostachya ‘Eureka’, button snakeroot, is a whopping 5 foot tall! Turtlehead, Chelone lyonii, is not your typical daisy-type native flower. Flowers of pink or white appear on plants adapted to shade/part shade conditions. Helen’s flower, Helenium spp., often goes by the unfair name sneezeweed because it’s not a weed and it doesn’t make one sneeze.  Cultivars range from tall to short, primarily in the red-orange-yellow area of the spectrum.

Daylilies, Hemerocallis, contribute a large number of varieties that bloom in August. ‘Challenger’ produces medium red flowers on 4 foot tall stems.  This variety was introduced into the nursery trade in 1949, proving that a plant doesn’t have to be a new introduction to be good.  Other daylilies that bloom in August include, ‘Happy Returns’, ‘Jen Melon’, ‘Jersey Spider’, ‘Mighty Chestnut’ and ‘Yuma’.

Patrinia scabiosifolia sports tiny sulfur-yellow flowers in grand clusters that make it a showy addition for August. If it’s pollinators you’re looking to attract, then plant the biennial Korean angelica, Angelica gigas. Wine-purple flowers appear on plants 2-4 feet tall. Clematis heracleifolia, tube clematis, is unlike any other clematis you’ve grown, with blue-purple tubular flowers on a 3 foot tall shrub.  Panicled hydrangea, Hydrangea paniculata, has numerous cultivars of show-stopping flowers including ‘Tardiva’ and ‘Grandiflora’.

The August garden need not be drab.  More about these plants and many others for the August garden may be found in this ISU Extension publication written by yours truly:

https://store.extension.iastate.edu/Product/Flowering-Plants-for-the-Late-Summer-Garden  .

The Extension Master Gardener horticulture helpline and open clinic hours are:

Mondays, 9:00 am to 12:00 noon, Washington County Extension, 402.426.9455

Tuesdays, 1:00 to 3:00 pm, Cuming County Extension, 402.372.6006

Wednesdays and Fridays, 9:00 am to 12:00 noon, Dodge County Extension, 402.727.2775

The Dreaded Japanese Beetle (Again)

Despite winter and spring conditions that we hoped could thwart them, the Japanese beetles are at it again. They fall on us as we mow beneath trees, eat our hard-won fruits as they multi-task, and drown in the dog’s water dish.  Here are some important considerations:

▪Japanese beetles do lay their eggs in the soil.  Managing Japanese beetle grubs to stop the damage to turfgrass IS effective. Targeting grubs IS NOT an effective means of damage prevention to trees, roses, and grape vines.  This is because there are ditches, fence lines and creek banks that are never treated for Japanese beetle grubs and emerging adults will always fly to where there is food.

▪Be aware that insecticide applications to anything with flowers on it will kill pollinators too.

▪For safety reasons, insecticide applications to food plants MUST be labeled for use on edible crops and the pre-harvest interval (PHI) followed.

▪It’s illegal to spray any systemic insecticide on trees. Systemic products are those taken in by plant tissues and distributed throughout the body of the plant.  The restricted-use insecticide chlorantraniliprole is effective against Japanese beetles but does not harm pollinators. Consider a tree service to apply chlorantraniliprole to trees as beetles emerge in June.

▪Japanese beetle feeding slows in August and plant damage decreases.  Yes trees do look lacy right now, but fortunately they do not die from Japanese beetle defoliation.

▪Japanese beetle traps are TOO good at drawing in JB. There are more Japanese beetles doing damage to plants in yards with traps than those without.

▪If collecting Japanese beetles from plants, the best time of day to do so is 7:00 in the evening. Collecting them at 7:00 results in a lower population of JB than at any other time of day. (Thank goodness for grad students who do the tedious work of collecting the data!)

▪Japanese beetles do not, I repeat do not, emit an aggregation pheromone.  An insect aggregation pheromone is an odor that is emitted to broadcast “supper at the Smith house.”  Rather, it is the plants emitting distress pheromones that draw JB to feast there.

So there you have it.  Japanese beetles are abundant, there is no one-size-fits-all remedy for managing them, and they tend to make plants look bad but not kill them. We take our lumps with gardening, along with the good.

 

Yellow Nutsedge

“What is this grass growing in my flower bed?” is a question I hear quite often now.  Rolling the stem between my fingers quickly determines this isn’t grass at all but the infamous yellow nutsedge.  Sedges are grass-like perennials that have triangular shaped stems.   If they grew at the same rate as turfgrass, many lawn owners would be OK with nutsedge growing there. Unfortunately, high heat and abundant moisture foster fast growth that easily outpaces the height of Kentucky bluegrass and fescue.   Yellow nutsedge is a particular problem in new flower beds and shrub borders if the previous space was occupied by turfgrass.  Dense lawns suppress the growth of yellow nutsedge and, once the turf is removed and landscape plants installed, yellow nutsedge can show up throughout. 

The use of “nut” in yellow nutsedge’s name comes from the small tubers, called nutlets, found at the end of roots. The presence of these nutlets helps to explain why the plant is so hard to manage at this time of the year. Removing yellow nutsedge by hand-pulling ensures nutlets will be left behind.  Once each nutlet begins to grow, where once there was one plant, now there are many. Herbicides used now will also be effective at eliminating the parent plant, but bear in mind herbicides do not translocate to the nutlets, so again, where once there was one plant, now there are many.  This isn’t to say we can’t hand-pull or use a herbicide, it just means diligence will have to be exercised to stay after new plants by repeating previous steps.

June 21 (the summer solstice) is the dividing point from when yellow nutsedge is relatively easy to manage to when it becomes a chore. Prior to June 21, plants have not reached the maturity necessary to form nutlets. Lawn herbicides containing the active ingredient Halosulfuron (Sedge Ender™, Sedge Hammer™, and Halosulfuron Pro™) applied before this date will be the most successful at managing yellow nutsedge in lawns. In gardens and borders, yellow nutsedge can be hand-pulled or spot sprayed with herbicides containing glyphosate, being mindful to shield desired plants.

From June 21 onward, the nutlets of yellow nutsedge are a tenacious survival mechanism that requires diligence (or acceptance) on our part to manage yellow nutsedge in our landscapes.

 

Caterpillars on Coneflowers

The silvery checkerspot caterpillar, Chlosyne nycteis, can be found right now, happily eating away on sunflower, aster, Echinacea, goldenrod and Rudbeckia.  The checkerspot caterpillar has branched spines on its back that are black in color. Sometimes the caterpillars will have an orange stripe or two.  Depending on weather conditions, there will be one to two generations per year. Once first generation caterpillars are an inch long, they will stop feeding and form a pupal case on foliage. As the growing season winds down, the second generation caterpillars will hibernate as third instar larvae.

The adult silvery checkerspot is a beautiful black, yellow and orange butterfly that is on the small side, with a wingspan around two inches across.  The black border on the wings will be edged with white dots. The females are more brilliantly colored than the males and males will have knobs at the end of the antennae, which helps them to find females.  This butterfly is a pollinator, feeding on flower nectar of the milkweed and red clover.

If gardeners can tolerate the loss of foliage on their plants, then by all means let the checkerspot caterpillars have at it because their population stability may be vulnerable. Caterpillar feeding tends not to destroy plants but there will be a lot of missing foliage. Where their feeding damage is a concern, grow an extra plant or two of their preferred chow and “herd” them by carefully breaking off the portion of the leaf they are on and placing it in the midst of their designated forage plant.  Harmony!

Herbicide Drift

A tomato plant sample was brought in today with curled stems and cupped leaves. Under-watering and fungal diseases were a few of guesses as to the wonky foliage while truly the blame lies with herbicide drift.  Drift occurs when desired plants receive an accidental dose of herbicide.  Depending on the herbicide, damage to vegetable plants and trees can show different symptoms--bleaching or yellowing, twisting, curling, and cupping of leaves. The most common culprits that cause curling and cupping leaves include 2,4-D (used to kill broadleaf weeds in lawns and pastures), dicamba (lawn and crop broadleaf weeds) and picloram (pasture broadleaf weeds). These herbicides are plant growth regulators, killing weeds by stimulating excessive growth and using up plant fuel, carbohydrates.

There is nothing that can be done to counter the effects of herbicide drift. Intuitively, we know there is some plant stress because distorted leaves don’t photosynthesize as well as normal ones.  Here are the most common modes of herbicide movement.

Wind

The greater the wind speed, the higher the likelihood the herbicide’s air-borne droplets will be    carried onto desired plants. Spray when wind speed is 3-7 miles per hour and set the sprayer to a larger droplet size.  Ask applicators in adjacent areas to be mindful of wind conditions and make applications when conditions are conducive for herbicides staying put.

Volatilization

A big word, a simple concept. When temperatures surpass 85° F, herbicides can vaporize and herbicide-laden vapors settle elsewhere, often where they are least desired.  If temperatures are hot, spray in the cooler morning hours.

Sprayers

Separate sprayers—one for insecticides and one for herbicides—keep herbicide residues from becoming a problem.  Mark the sprayers so you don’t forget!

Lawn Clippings, Soil, Compost and Manure

Lawns or pastures treated with herbicides can be a problem when grass clippings, soil, compost, hay, and animal manure from these sites are used in gardens and around trees. Knowing the history of how these sites are managed will help determine if these materials can be used.         

Herbicides moved via wind, volatilization and contaminated sprayers tend to be one-time incidences.  As vegetable plants and trees put out new growth, the leaves and stems will most likely be their normal shape and size, indicating plants have outgrown the effects of the herbicide.  The damage to vegetable plants via herbicide-laden lawn clippings, soil, compost, hay, and manure is ongoing, particularly if picloram was used on the lawn or pasture.  Consequently, vegetable plants don’t recover and should not be eaten.

The Extension Master Gardener horticulture helpline and open clinic hours are:

Mondays, 9:00 am to 12:00 noon, Washington County Extension, 402.426.9455

Tuesdays, 1:00 to 3:00 pm, Cuming County Extension, 402.372.6006

Wednesdays and Fridays, 9:00 am to 12:00 noon, Dodge County Extension, 402.727.2775

Mulch and Hot Weather

Mulch is an aspect of the landscape that doesn’t provoke much thought.  Wood chips or rock?  Landscaping fabric or not?  The reality is that the right kind of mulch, applied to the proper depth, has a BIG impact on plant health, especially during the heat of summer.

Root function stops when soil temperatures reach 85°F and higher.  This means no water and nutrient uptake occurs when soil temperatures are hot. No water moved through roots leads to leaf burn and heat stress. Woodchips and shredded bark act as insulation, protecting the soil from direct sunlight and buffering air temperature extremes.  The result is cooler soils that favor root uptake of water.

Mulched trees and trailing plants that are lucky enough to shade their own roots have the advantage over ones placed in rock mulches, where the absorbed heat dissipates well into the evening hours and keeps soils hotter longer.  Adding insult to injury, landscaping fabric used beneath rock interferes with root respiration (where plants roots take in needed oxygen). 

The depth of woodchip and bark mulches plays a role in plant health. A 2-4 inch layer of mulch is the right amount to keep soils cooler while allowing root access to oxygen.  Mulch piled higher than 4 inches, or mulch that extends up against the crown of trees and shrubs (the dreaded mulch volcano!) can be as detrimental to tree health as rock mulches are.  More is definitely not better!

The extent of woodchip and bark mulches also plays a role in plant health.  Devoting less real estate to lawn and more to mulching beneath tree and shrub canopies extends the benefits of mulch to more of the root zone. The workhorses of a root system, the fine root hairs, are better developed and there are more of them when growing beneath wood chips than beneath turfgrass. What is a good size for a mulched bed?  At a minimum, mulched areas should extend out at least 4 feet from the tree trunk.

High temperatures can contribute to plant stress but incorrect mulching need not be one of them.  Find out more about mulching by following this link: http://extensionpubs.unl.edu/publication/9000016361444/mulching-the-landscape/ .

Gardening with Children

When gardening with children, it’s important to encourage use of all the senses. 

▪For touch, experience plants that are soft, such as lamb’s ears (Stachys); prickly, like pumpkin on a stick (Solanum integrifolium); and stickiness of the native hedge apple (Maclura pomifera). 

▪When it comes to fragrance, we often think of flowers, but leaves and fruit are fair game too. Black walnut (Juglans) leaves and nuts have a distinct pungency that helps with identification.

▪Encourage appreciation of sound as wind moves through tall grasses or causes rattling of the pods of false indigo (Baptisia).

▪Set up your own taste test by pairing store-bought strawberries against their juicy fresh-from-the-garden counterparts so children know what food should really taste like.

▪We use the sense of sight all the time but many of those times we fail to really SEE things. Engage children in the search for the wishbone at the center of wishbone flower (Torenia) or counting the number of pollinators on a wildflower.

Consider planting a themed garden to mix things up and add some fun:

▪An alphabet garden can be made up of both food and ornamental plants (“a” is for alyssum, “b” is for beans, etc.)

▪A zoo garden features plants that have an animal in their name. Some fun plants are zebra grass (Miscanthus), hen and chicks (Sempervivum), and pigsqueak (Bergenia).

▪ Grow cilantro, tomatoes, hot peppers and onions in a circular garden (to mimic the round shape of a tortilla) to make a salsa garden. 

▪Plant a pizza garden by growing basil, tomatoes, sweet peppers and onions. Then have a pizza-making party!

▪A three sisters garden is named for the Native American tradition of planting corn, beans and squash together because they benefit one another. Corn supports the beans as they climb, beans provide nitrogen (a needed plant nutrient), and squash keeps everyone’s roots cool.

Gardening with children passes along science disguised as hands-on fun.  This age old tradition creates a new generation of gardeners who can grow their own food and have an appreciation for the green world around them.

The Best Way to Remove Problem Trees

Seedling trees come up in the oddest places, and in some cases, totally unnoticed.  In the neighborhood I drive through, I observed a mulberry tree growing up through a shrub rose.  The mulberry thrived, gradually completely shading out the rose.  Eventually the rose owner noticed the mulberry and tried to remove it, resulting in the loss of both plants.  The key lesson here, other than mulberries being aggressive growers, is that by simply taking note of what is going on in the landscape and taking action while problem plants are young, time and effort is saved later.

Tree seeds have multiple ways of dispersing—wind and birds being the most common. Mulberry, boxelder, ash, silver maple, cedar and Siberian elm are often the worst culprits, producing a huge number of seeds and sowing themselves into cracks, finding a place amidst desired plants and insinuating themselves in the tiniest patch of bare earth. The flying saucer-shaped seeds of Siberian elm and the winged seeds of silver maple are excellent mechanisms for wafting into new places. The seeds of mulberry and cedar are a favorite food of birds, with the seeds moving unscathed through their digestive tract. Wherever birds roost, droppings are deposited along with a healthy dose of fertilizer to get the seedlings off to a good start.

Seedling trees that come up in lawns are easily managed just by the act of mowing, killing them at a vulnerable size. Shrub and flower borders, vegetable gardens and containers aren’t mowed so require diligence on our part to keep volunteer trees from becoming monsters.  Approaching this task is easier when trees are small, making the chainsaw and loppers unnecessary, especially when complete removal consists of pulling out seedlings between the thumb and forefinger. Larger trees that have been cut down, only to re-sprout, have enough sugars stored in their root system to make removal by pruning alone unlikely. When digging out problem trees is not a possibility, drilling multiple holes into the stump and applying a herbicide is a simple way to address problem trees.

If your own financial circumstances allow for the hiring of landscape management professionals, then having eyes on the landscape isn’t going to be a problem. Lacking a professional landscaper, monitoring what is going on in the landscape is the next best thing to address potential issues before they become real problems.  

 Nebraska Extension Master Gardeners can answer your gardening and plant questions!  The horticulture helpline is available for questions from the public at these dates and times:

Mondays, 9 a.m. to 12:00 noon, Washington County Extension, 402.426.9455

Tuesdays, 1:00 to 3:00 p.m., Cuming County Extension, 402.372.6006

Wednesdays and Fridays, 9:00 a.m. to 12:00 noon, Dodge County Extension, 402.727.2775

Peach Leaf Curl

Peach leaf curl is prevalent this spring.  The fungal pathogen, Taphrina deformans, causes leaf puckering and unusual coloration, with bright red, yellow, lime green, or a combination of all three colors on one leaf.  Infection occurs at bud swell and bud break, when spores, overwintering on twigs and buds, infect emerging leaves. The distortion of leaves inhibits photosynthesis and early defoliation occurs, all of which affects the tree’s ability to produce peaches. If infection is severe and occurs over several growing seasons, the disease weakens the tree.

Cool, wet springs are highly conducive to the development of peach leaf curl on peaches and nectarines.  While the disease tends not to infect the fruits, fungal infection of the fruit is possible when temperatures and precipitation levels continue to favor the pathogen. As the disease matures, leaves become thickened and covered in powdery spores. Affected leaves may drop from the tree or continue to hang on branches.

Once the fungus is present on leaves, fungicide applications do not provide much in the way of protection or control. The key to keeping disease incidence low is to target overwintering spores. Dormant oil is a heavy, viscous oil that works by suffocating fungal spores on twigs and buds. Applications are best applied twice, once in late November and the second in late March when temperatures are above freezing. Other fungicide options include chlorothalonil and copper-containing fungicides.

Growing Asparagus

Cooks love the earliness that fresh asparagus provides. Gardeners love it because it’s perennial and relatively worry-free. If you’ve not grown asparagus, this spring would be a good time to plant a few crowns to find out for yourself just how easy it is to grow.

Asparagus can be started in one of two ways.  Seeds are an economical way to go but add an extra year onto when harvest can begin. Asparagus can also be started from year-old crowns purchased from garden centers, box stores or catalog companies. ‘Mary Washington’ is an asparagus variety that has been around since 1949 and is still readily found today. The ‘Jersey’ series of asparagus, consisting of ‘Jersey Knight’ and ‘Jersey Giant’ are highly touted but lack hardiness when temperatures are below -30° F and snow cover is minimal.  Newer varieties better suited to our winters include ‘Purple Passion’ and ‘Viking KB-3’.

Asparagus is a dioecious species, meaning there are male plants and female plants.  Female plants produce red “berries” that drop to the ground, seeding new plants into unexpected places like creeks, ditches, and roadsides. If not sprayed with a pesticide, spears can be harvested from these wild plants. (My brother has a list of locations of wild asparagus and jealously keeps it secret!) While the berries are not poisonous, they are inedible. Male plants tend to live longer and produce more spears.

Because asparagus is a long-lived plant, care should be given to soil preparation. A pH of 6.5-7.0 is best for good growth.  Sulfur may be added to bring the pH lower if the pH is above 7.0. Asparagus plants appreciate a deep loamy soil so work compost into the site if the soil is sandy or clayey.  Soils in our area tend to be abundant in phosphorus and potassium, so a 30-0-0 fertilizer applied at of a rate of ½ pound per 100 square feet provides the nutrition for good growth. 

To plant asparagus crowns, dig a trench 6-8 inches deep and 12 inches wide.  Spread out the roots around the crown and add two inches of soil.  (More soil is added as plants grow.) Crowns should be spaced 12-18 inches apart in rows 5 feet apart. 

Weeds and the asparagus beetle are two common problems. Keep in mind that tilling to remove weeds has the potential to damage asparagus crowns too.  Hand-pulling weeds and mulching with shredded newspapers or wood chips keeps weed numbers low while plants are establishing.  Once the stems develop ferns, the plants will shade out would-be competitors. The asparagus beetle, both the adults and the immatures, feed on the spears, stems, and foliage of asparagus, causing bending or twisting of the spears, along with brown spots from the feeding site. If damage from the asparagus beetle warrants control measures, use an insecticide labeled for use on edible crops such as insecticidal soap or spinosad.

Asparagus can be harvested during its third growing season.  Bend the spears to snap them off or use a knife to do a clean cut. Once most of the patch has more pencil-sized spears than plump ones, it’s time to quit harvesting and let plants re-build their reserves.  Cut the stems and ferns back to the ground in the fall after the entire plant has turned brown.  This allows the plant time to transport carbohydrates from the leaves into the root system.  This also removes overwintering eggs from the asparagus beetle.

More information may be found here:  https://extension.umn.edu/vegetables/growing-asparagus .

Nebraska Extension Master Gardeners can answer your gardening and plant questions!  The horticulture helpline is available for questions from the public at these dates and times:

Mondays, 9 a.m. to 12:00 noon, Washington County Extension, 402.426.9455

Tuesdays, 1:00 to 3:00 p.m., Cuming County Extension, 402.372.6006

Wednesdays and Fridays, 9:00 a.m. to 12:00 noon, Dodge County Extension, 402.727.2775

Vegetable Gardening 101

Nothing provides greater satisfaction than to grow your own food.  It’s also really easy to start, with a small investment in some seeds, a few transplants, and a container or plot of land.

A basic requirement in vegetable gardening is a clear understanding that there are cool season vegetables—those that grow and produce best when temperatures are chilly and frost is still a common thing—and warm season vegetables—those that grow abundantly when frosts are past and temperatures are warm.  Cool season vegetables include kale, lettuce, peas, radishes, broccoli, cauliflower, cabbage, potatoes, onion, and spinach, to name a few.  Warm season crops are comprised of eggplant, pepper, tomato, tomatillo, beans, okra, New Zealand spinach, cucumbers, melons, corn, basil, summer squash, and winter squash.

Cool season vegetables will develop flower stalks and fail to produce if planted when temperatures are too warm.  Likewise, warm season vegetables will need protection if planted when frosts are still common. Mother’s Day serves as a good date to gauge if it’s time to be planting warm season vegetables and marks the end of spring planting of many cool season crops. Gardeners have the added benefit of getting in a second crop of cool season vegetables by planting them in late August. Though temperatures may be still warm in late August, cool season seedlings will benefit from lattice or some other temporary shade structure until temperatures cool.

From here, it is helpful to know which vegetables can be started by directly sowing seeds into the garden and those that need a head start, such as those started early indoors or purchased transplants from the garden center.  Lettuce, peas, spinach, radishes, kohlrabi, beans, cucumbers, melons, corn, basil, and squash are easily directly sown from seed into the garden. Those that benefit from the extra time provided by starting them early indoors are broccoli, cauliflower, cabbage, Brussels sprouts, eggplant, pepper, tomato and tomatillo.

Many new gardeners purchase every vegetable for their garden as cell-pack transplants.  Not only is this a costly way to vegetable garden, it also limits the vegetable varieties to choose from. Starting seeds inside to transplant later into the garden or to be directly sown offers a cost savings and a tremendous variety of possibilities missing from cell-pack choices. An excellent resource for getting started is from Iowa State University Extension, “Planting a Home Vegetable Garden,” available at: https://store.extension.iastate.edu/product/4134 .

Want to know more about vegetable gardening and the possibilities that seeds offer?  The Nebraska Extension Master Gardeners in Washington County are teaming up with the Blair Library to sponsor a seed library. People can check out seeds to grow in their garden, then return collected seeds to the library at the end of the gardening season.  Kickoff for the new seed library is a seed exchange, Saturday, May 18, from 1:30 to 3:00 p.m. at the Blair Library, 2233 Civic Drive. An “Ask the Master Gardener” table will be featured, along with a program on “Beginning Vegetable Gardening” by me at 1:30 p.m.

Nebraska Extension Master Gardeners can answer your gardening and plant questions!  The horticulture helpline is available for questions from the public at these dates and times:

Mondays, 9 a.m. to 12:00 noon, Washington County Extension, 402.426.9455

Tuesdays, 1:00 to 3:00 p.m., Cuming County Extension, 402.372.6006

Wednesdays and Fridays, 9:00 a.m. to 12:00 noon, Dodge County Extension, 402.727.2775

 Managing Weeds in the Garden

Weeds may be our least favorite topic but still one of the driving forces behind phone and email questions right now, with “How do I kill...?” leading the discussion. Weed identification may seem immaterial, after all, the consuming focus is to be rid of the pesky plant, but in reality, this should always be the first step.  Why?  Because determining if the weed is an annual or perennial will help to direct the most effective management strategy.

Let’s start with annual weeds. In this category we have foxtail, crabgrass, henbit, Pennsylvania pellitory and speedwell to name a few.  For annual weeds, plants rarely expend much energy to develop a robust root system.  Instead, the plant’s life cycle depends on producing copious amounts of seeds before the growing season ends and the weed dies. Keep in mind that herbicides work best when translocated into the root system, resulting in effective management of the weed. With annual weeds, however, movement within the plant is upward and little in the way of herbicide is moved into the roots.  Dieback of the foliage occurs but the weed can and does grow back.

A better strategy would be to make use of pre-emergence herbicides for annual weed management. A pre-emergence herbicide targets germinating seeds, killing them before they even break the soil surface. For winter annuals like speedwell and henbit, the application of a pre-emergence herbicide takes place around September 1. For warm season annuals like purslane and spotted spurge, an application around May 1 is best.

Perennial weeds are different in that their root system survives our winters, putting on fresh growth each spring.  Brome, dandelion, ground ivy, wild violet and stinging nettles are just a few of the many perennial weeds. For perennial weed management, their winter survival strategy can be used against them. In the fall, as perennials ready for winter, transport of sugars into the root system ensures survival for plants.  Post-emergence herbicides applied at this time are very effectively moved into the root system along the sugar pathway. The result is more effective management. Does this mean we shouldn’t try to manage weeds in the spring and summer?  Not necessarily. After all, the plants will be growing robustly during this time, so the point is to use herbicides to slow growth while recognizing that management efforts will have greater efficacy with a fall application.

Yellow nutsedge management requires a different strategy, utilizing a post-emergence herbicide containing the active ingredient either halosulfuron or sulfentrazone.  Application needs to take place before June 21 (the summer solstice) to bypass the plant’s ability to create underground structures, called nutlets, that are resistant to herbicides.

Patience is a virtue when dealing with any kind of weed issue. Rarely does one application of a herbicide take care of the entire problem. Identifying the plant in question leads to an understanding of the plant’s life cycle, which then directs management strategies. Weeds of Nebraska and the Great Plains from the Nebraska Department of Agriculture is a great resource for identifying weeds, with color pictures and descriptions of the plant. Order forms to purchase the book may be found here: http://www.nda.nebraska.gov/forms/nw11.pdf .    

Mulch Volcanoes—A Harmful Practice for Trees

Too often the mindset is if a little is good then a lot must be better. So it goes with the spring task of mulching. A “mulch volcano” is the tongue-in-cheek term given to those copious heaps of woodchips surrounding a tree.  No one knows exactly where this harmful practice came from but all it takes is for one person in a neighborhood to do it and suddenly this ill-advised practice is everywhere.

There are two detrimental effects to mulch volcanoes. First, roots respire, meaning they take in oxygen and release carbon dioxide.  This exchange of gases, as it is known, takes place in the upper 18 inches of soil.  It’s no accident that roots proliferate in the top 18 inches because this is where oxygen is most readily available.  Bring in a boatload of mulch and suddenly the lower roots no longer have access to oxygen.  This leads to stressed and dying roots which in turn stresses the tree.  A stressed tree has less defenses than their properly-mulched counterpart, leading to susceptibility to otherwise-minor insect and disease problems.  Mulch piled around tree trunk

The second detrimental effect of a mulch volcano has to do with the tree trunk. Tree bark is well suited to protecting the trunk from sunlight and wind.  Mammoth piles of mulch surrounding a trunk, however, keep bark constantly moist, fostering decay.  Over time the bark rots, exposing the conductive tissue beneath the bark to decay as well. This negatively impacts the trunk’s function to move water upward/sugars downward and the structural integrity of the tree.  (I once walked through a neighborhood after a windstorm and every tree lying on the ground broke below the mulch volcano, showing lots of symptoms of decay.

Written as an equation, it would appear as:

Too much mulch = stressed roots + rotting trunks → unhealthy trees → increased susceptibility to (otherwise minor) insect and disease problems + structural instability = more $ to treat + increased probability of tree death.

What is proper mulching?  A two to three inch layer of shredded bark or woodchips, starting two inches from the tree and extending out to a distance of 4 feet from the trunk is best. Never use landscaping fabric as this interferes with the exchange of gases at the root zone. Mulch decays over time, which enriches the soil, so renew the mulch as needed to maintain a depth of 2-3 inches.mulching appropriately distributed around tree trunk

What can you do?  Ask your landscape manager about their tree mulching practices and, if it is done incorrectly, ask them to re-do it. Neighborhood associations and SIDs can share information within their communities to educate those who like to do the work themselves. Make sure your own trees are properly mulched, talk about it with others and then show it off!

The benefits of proper mulching are manifold—suppression of weeds, cooler soils in hot weather, protected soils in cold weather, keeping string trimmers and mowers away from tree trunks, and fostering microbial activity for healthy roots.  The time and effort to properly mulch is well worth the effort for vigorous growth and a happy tree. 

Henbit, Ground Ivy and Speedwell

Three weeds we see at this time of year resemble each other so closely that it is often confusing as to which is which. Henbit, ground ivy, and speedwell are flowering right now so are easy to notice.  I’ll admit, conversations about weeds are some of people’s least favorite, but talk we must and to this end identification of the weed is a key first step.  Why? After all, isn’t a weed a weed and all weeds should be eradicated by any means? Like most things involving plants, it’s just not that simple. Remember that pollinators like these plants for the nectar they provide in early spring.  Devoting a small space to these plants is an excellent way to help them out while minimizing square footage overall. So if management is a must, identifying the plant first leads to information about its life cycle, which in turn gives clues about effective ways to manage it.

Henbit, Lamium amplexicaule, is a winter annual and a member of the mint family. The purple flowers begin in March and continue through May.  You’ve probably seen this plant numerous times—it is the carpet of purple across fallow fields. It can be distinguished from ground ivy, which also blooms purple, by the leaf attachment. The upper leaves on henbit are sessile, meaning there is no stalk attaching the leaf to the stem.  (A way to remember this trait is that the hen squats on the stem!) Henbit spreads primarily by seeds.ground ivy

Ground ivy (Glechoma hederacea), also a member of the mint family, differs from henbit in that it is a perennial. All leaves of ground ivy will have a stalk (called a petiole) attaching it to the stem.  Ground ivy grows very well in urban settings, preferring shaded sites but will also show up in rough areas, such as roadsides. Ground ivy will spread by seed but it is more common to see the plant spreading by root development along stems.speedwell

Speedwell, Veronica agrestis, is not in the mint family at all, so the plant won’t have a strong aroma when mowed.  Mowing really isn’t a means of management because speedwell really hugs the ground.  The flowers of speedwell are tiny, just 1/8 of an inch across and sky blue in color. A winter annual, it shows up in areas of thin turf.  Speedwell spreads by seed.

Since henbit and speedwell are winter annuals, a pre-emergence herbicide applied around Labor Day in the fall does an excellent job of keeping weed numbers down.  A three-way herbicide (one that has 3 herbicides in one product) and herbicides containing triclopyr provide some post-emergence control for henbit and speedwell.  Triclopyr is a good management option for ground ivy with better control achieved when the herbicide is applied in the fall, interfering with the plant’s ability to store food for winter.