This Week's Horticulture News/Information

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 Vegetable

Direct Sow Seeds

Set Out Plants

Comments

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. 

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.

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 (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, 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.

Flooded Vegetable Garden Plots

Looking forward to the vegetable garden this spring, it’s easy to think that now that the flood waters have receded, our gardening season can carry on as usual.  While many of the callers to Extension are aware of potential dangers of gardening on a flooded site, the exact way forward is a little unclear.  Here is a synopsis of how flooding affects food safety in our vegetable gardens and orchards.

Flood waters carry contaminants, like E. coli and Salmonella, and an array of other stuff, like petroleum products, pesticides, dirt and sand. Mother Nature has in her toolkit some truly wondrous ways of dealing with contaminants, sunlight and soil microbes being two of them.  It takes time for these to complete their work, however, so until contaminants are broken down and degraded, keep in mind some food safety guidelines.

Much of what we know about food safety, flooding, and contamination come from research conducted on the use of fresh manure in gardens. From this research, two blocks of time are key—the 90 day interval and the 120 day interval.

The 90 day interval starts when flood waters recede and extends to when harvesting for eating takes place.  This refers to fruits and vegetables not in direct contact with the soil.  So tomatoes (staked), peppers, eggplant, cucumbers (trellised), sweet corn, tomatillos, apples, pears and grapes fall in to this category.

The 120 day interval follows the same concept but is extended to those fruits and vegetables that are in direct contact with the soil.  This includes strawberries, tomatoes (un-staked), muskmelon, watermelon, radishes, lettuce, carrots, potatoes, spinach, asparagus, cucumbers (un-trellised), morel mushrooms, herbs, and rhubarb. If the interval extends beyond harvest readiness, then discarding of the produce is recommended.

Other important considerations:

                ▪Seeds and transplants can be planted into previously flooded soils before the time interval has elapsed as long as the harvest extends after the 90-day or 120-day intervals.

                ▪Removal of transported soil and sand from the garden site does not negate the 90-day and 120-day rules.

                ▪Cooking/canning kills some bacterial and viral contaminants from floodwaters but not all.

                ▪Some seasonal fruits and vegetables will not be candidates for eating this spring, perhaps even this year.

                ▪Harvesting before the interval has passed to store the produce in the refrigerator to wait out the remaining time does not count. Sunlight plays an important role in degrading contaminants.

                ▪Vigorous scrubbing and chlorinated solutions destroy produce quality and do not dislodge all bacteria and contaminants from cracks and crevices in fruits and vegetables.

Be Mindful of Flooded Areas When Hunting Morels

As morel mushroom hunting season approaches, be mindful of food safety.   It’s important to remember flood waters don’t carry just water.  There is a host of unsavory things that are downright dangerous—

                ▪Human disease pathogens from raw sewage,

                ▪Pesticides carried from farm fields and lawns on soil particles and plant residue,

                ▪And rubber and petroleum products from cars, boats and farm equipment. 

While there is NO washing technique that will completely remove all contaminants from morels, the heat from cooking them will likely kill human pathogenic bacteria and viruses. This is not true for pesticide and petroleum residues.  These products can be harbored in the tiniest crevices and tissues of the morel and are extremely resistant to removal by washing.  Since we can’t know all of the contaminants flood waters carry, it is far safer not to eat morels gathered from flooded areas.

Morel mushroom hunters should take note of their usual gathering sites.  High ground is going to be best for searching for morels as these sites are less likely to have been flooded.  If corn stalks and grass are caught high around brush and fences, this is a clear indication the site was flooded and morels should not be gathered. Again, it’s better to ere on the side of food safety.

For those who have been gifted or have purchased morels, be sure to ask questions from the gatherer about where the morels came from.  People with compromised immune systems, such as children, the elderly and those who are ill, are adversely affected by the flood water contaminants that morels can harbor.

Never use soap to clean morels. Instead use 2 tablespoons of bleach to one gallon of water for washing, followed by thorough rinsing with clean water. 

While it is hard to miss out on this tasty spring treat, if we receive no more flooding, morel mushroom aficionados can expect gathering with no reservations next spring.  For more flood resources, go to flood.unl.edu

Flood Recovery and Plants in the Landscape

The flooding and subsequent ponding has a profound effect on trees and shrubs in the landscape. The contaminants these waters carry negatively impact vegetable garden sites and orchards.  Here are some flood resources to address residents’ concerns.

Food safety in vegetable gardens and orchards after a flood*: https://grobigred.com/2019/03/22/gardenflood/amp/?__twitter_impression=true  by Nebraska Extension Urban Ag Educator John Porter

Turf Recovery After Historic Flooding: https://turf.unl.edu/turfinfo/3-25_Flood_Recovery.pdf by Roch Gaussoin and Bill Kreuser, University of Nebraska-Lincoln

Understanding the Effects of Flooding on Trees: http://store.extension.iastate.edu/product/Understanding-the-Effects-of-Flooding-on-Trees-Sustainable-Urban-Landscapes-PDF , Iowa State University Extension

Helping Flooded Trees and Shrubs: https://www.ag.ndsu.edu/publications/lawns-gardens-trees/helping-flooded-trees-and-shrubs , North Dakota State University Extension

*With morel mushroom hunting season approaching, be aware that mushrooms collected from areas impacted by flooding should not be eaten. This would also be true for other wild edibles, as well as domestic perennial crops like asparagus and rhubarb.

For more resources on flooding, go to flood.unl.edu or email questions to floodresponse@unl.edu .

Flooding and Ponding around Trees

The 2019 spring flood has had a devastating impact for all parts of the landscape, including trees.  While the extent of the damage to trees may not be realized for years, how and if trees survive depend on several factors.

▪Certainly that the floods came when the trees were dormant is a factor in their favor. Flooding is always hardest on actively growing trees.

▪The length of time tree roots are submerged will determine whether they can survive.  The water left behind after a flood (ponding) is more detrimental to trees because water replaces air in soil pore spaces.  Since roots require oxygen to complete their metabolic processes, the lack of oxygen in waterlogged soils causes root death.

▪Some tree species, like the baldcypress, cottonwood, and willow tolerate the waterlogged conditions that flooding brings, mainly because they are able to regenerate new roots relatively quickly.  Others, such as sugar maple, redbud, shagbark hickory and spruce are intolerant of waterlogged soils and will show symptoms of yellow leaves, lifting bark, brown needles, defoliation and crown dieback because of their slow regeneration of new roots.

▪Healthy trees, like healthy people, naturally have more resiliency when adverse events happen. The more robust the tree, the better able it will be to marshal the defenses necessary to survive the flooding. Healthy trees will have greater root regenerative capacity and more resistance to secondary insects and diseases that overcome unhealthy trees.

▪The stuff the floodwaters carry is a factor when determining if trees will survive.  Deposited soil, raw sewage, petroleum products and a host of other contaminants are challenges to root survival.

What Can Be Done

Replace soil around flood-exposed tree roots. Likewise, remove all flood-deposited soil around trees, clearing away all excess around the trunk itself and continuing beyond the dripline. For trees toppled because of dislodged roots, small and medium-sized trees can be righted and staked for stabilization. Remove rock, landscaping fabric, and mulch (if it hasn’t washed away) to allow sunlight and air circulation help with water evaporation from soils. Plan to remove broken branches at the proper pruning time of April, May or June. Although it is human nature to want to help, trees stressed due to flooding should not be fertilized.

 More information about how floods impact plants may be found here: https://flood.unl.edu/horticulture .

What Kills Trees

Trees in native undisturbed sites live, on average, to be about 150 years old.  Downtown trees have a life expectancy of 7-17 years; suburban trees 30-40 years; and rural trees 60-70 years.  Why is there such a difference in life expectancy between trees in native sites than those in disturbed sites? Certainly there are acute factors, like hail, herbicide drift and insect infestations that can kill trees but the chronic issues overwhelmingly pre-dispose trees to shortened lifespans.

While difficult to see, pre-disposing effects are basically unhealthy environments. This leads to unhappy trees with dysfunctional roots.  Some common pre-disposing factors include:

▪Trees are planted too deep

▪Grade changes around existing trees

▪Soil compaction

▪Trees are overwatered

▪Exposure to long term drought

▪Live in confined root spaces

▪Have girdling roots

▪Are not winter hardy

▪Are not adapted to growing in soils with a high pH.

Most of us do not recognize a tree in decline until 12-20 years after the tree has been planted. Amazingly enough, unhappy trees will grow but lack the energy to really thrive. Too often, this means conditions are not reversible and the problem cannot be remedied.  What tree owners do notice are acute conditions—leaf scorch, chlorosis, early leaf shed, smaller leaves and reduced tree stability—symptomatic of the larger problem of unhappy trees with dysfunctional roots.

Trees have a limited ability to adapt to adverse growing conditions. Those living in adverse conditions are subject to a decline spiral, succumbing to short term “problems” that healthy trees growing in good environments can readily withstand. If we select, plant, and manage trees with the intention that they not only survive but thrive, many tree problems are preventable, resulting in longer lived trees.

Check out Cornell’s Woody Plant Database to search for trees and shrubs suited to specific conditions:  http://woodyplants.cals.cornell.edu/home .

What is Nebraska Extension ProHort Education?

ProHort, short for Professional Horticulture, is research-driven education for individuals in the tree, lawn, landscape maintenance, and garden center industries, as well as anyone who wants to hone her/his skills in the areas of botany, insects, soils, landscape design, plant disease, trees, wildlife damage management, turfgrass, and Integrated Pest Management (IPM). While people participating in ProHort education train right alongside Nebraska Extension Master Gardeners, there is no volunteer component associated with ProHort education nor do people have to apply to participate.

Classes begin on Wednesday, March 6 at Dodge County Extension, 1206 West 23rd Street in Fremont and continue for an additional five consecutive Wednesdays, culminating in a diagnostic lab on Wednesday, June 5.  Altogether, thirteen topics are covered during the course, with a new topic each morning and moving to a different topic in the afternoon.

Classes are taught by educators from Nebraska Extension, as well as the Nebraska Forest Service. Classes qualify for continuing education units (CEUs) required for re-certification with the Nebraska Arborists Association and the International Society of Arboriculture.

Those wishing to participate in ProHort Education have two options—classes are offered as stand-alone training sessions at a per-topic cost or they may opt to attend the entire course, which is a savings over the cumulative per-topic cost. The ProHort handbook is provided to those attending the full course.

More information and registration information may be found on the Nebraska Extension in Dodge County Facebook page or by contacting me at 402.727.2775.

Plan…Plan…Plant!

In carpentry, there is an old adage urging us to measure twice and cut once. The same can be said when it comes to plants.  Planning is the least expensive of the plant selection process, simply requiring a little of our time to talk to experts and glean information from catalogs and web sources.  I’ve never had a client say, “Gosh, I’m really sorry I planned and did the research!”  Rather, I hear from clients who didn’t adequately plan and are now dealing with how to help plants survive or costly removals.

Most plant failures come from a shortfall in adequate information.  A sibling was ready to plant a Japanese maple in their front yard, the site of new construction with poor soils and little in the way of wind blockage, until someone (me!) mentioned this wouldn’t work. Knowing which plants can handle the rough places and which need more protection plays a huge role in plant selection.

Another example of inadequate planning is when plant success creates an issue, such as the cute little blue spruce planted next to the driveway. That little tree that was so adorable is now covering the driveway and obstructing the driver’s site line for vehicle and pedestrian traffic. I once watched a neighbor struggle with this very issue, first pruning out the lower limbs and then disliking the result so much that the tree was removed. A $1000 bill later fixed the safety problem but not without cost to the wallet and loss of a healthy and handsome tree.

Nebraska Extension experts, Extension publications, garden catalogs and garden centers are good places to start.  When doing a Web search, type in the subject followed by the phrase “site:.edu” to narrow the search to research-based information.  The closer the area is to your location, the better fit for your own growing conditions. Keep in mind that listed plant dimensions are for optimum growing conditions, which the Midwest is not, so figure 80% of that number will give a better indication of the height and width of the plant, allowing you to space plants accordingly.

Be aware of glowing terms that don’t give a true picture of what the plant is like.  “Spreading” can be another word for rampant or invasive. The terms “compact” or “dwarf” are relative terms, meaning that a compact burning bush is not a neat and tidy two foot tall shrub.  It simply means a compact burning bush will be smaller than a regular burning bush (which grows to eight feet tall and wide!)

New projects are a great time to address soil conditions and the grade of slopes, which are very difficult to correct after plants are planted.  Adding compost to loosen clay soils and beef up sandy ones should be done early to ensure plant success.  Changing the grade should be done early, too, to keep from damaging the roots of established plants.  By doing the research early, you’ll be better informed to discard ideas for bringing in or removing soil around established trees, which can kill them.

Taking Care of Poinsettias

I had a client call me one September day and asked if it was time to bring her poinsettia into the light. Oh yes and by the way, she mentioned the plant had been stored in the closet for the past nine months. Hmmm… On the positive side of things, I thought it was great she was aware that the absence of light instigated the poinsettia’s coloration. Still, after 9 months with no water and sunlight, it was safe to say the plant was toast and it was best to throw it out.

How does one go about keeping a poinsettia, you ask?  First, the newer hybrids are better than ever about keeping their leaves and colorful bracts (the flowers are the tiny yellow things at the center) well into March.  So it’s no big task to keep them in a bright window with regular watering to enjoy the poinsettia for quite some time.

Once the stems lose a lot of their leaves through senescence (the natural aging and loss of leaves) or because you forgot to water it once, you have two options for moving ahead.  One is to cut back the stems by half.  The poinsettia is a shrub, so you will get lots of new shoot growth from the shortened stems. The other option, and one that takes a little finesse, is to make it into a lollipop. Called a standard, the poinsettia can be trained into a single tall stem with a ball of leaves at the top.  A poinsettia standard is created by selecting a strong, upright stem and then removing all of the remaining stems. Encourage new growth at the top by removing sprouts along the stem.

Poinsettias are native to Mexico and so do wonderfully during our hot summers.  Before moving them to their outdoor location, make sure there is no danger of a late frost and then acclimate them to the outdoors through the process of hardening off. Once outdoors, plants can be moved to larger pots, fertilized regularly and pruned according to the desired shape. 

Bring in plants before the first frost and place them in an east, west or south-facing window. Instigating the coloration of the bracts can be simple.  If room lights remain off during the evening hours AND no street or yard light leaks in through the window during the evening, the poinsettia will develop colorful bracts on its own.  Barring that, then begin the process in late September by placing the plant in a dark closet from 5:00 pm to 8:00 am and then moving it to a bright window from 8:00 am to 5:00 pm each day.  Once the coloration of the bracts begins, the plants can be moved and left in a bright window.

With all the wonderful color poinsettias provide, it’s a great indoor plant to grow your own fresh air!  More information can be found here:  https://lancaster.unl.edu/hort/articles/2007/poinsettia.shtml .

Composting—Even in Winter

Whether you are new to composting or an old hand at it, there is a technique that can, or already does, work best for you. My favorite composting adage is one supplied by Roger Swain former host of public television’s The Victory Garden: “Throw some green stuff in, throw some brown leaves in, throw in a few handfuls of dirt to activate everything, and you’ll get compost!”   People into the science of composting like to throw out terms like “the carbon-nitrogen ratio” and “aerobic and anaerobic bacterial decomposition.”  These are great terms to use, and if you understand them, can be implemented in your composting regime.  But I like Roger’s approach, mostly because it’s simple and I never want to see anyone NOT compost because it’s too complicated.

Master Gardener Wally had a novel approach.  He would dig a small hole in his flower bed and then empty in his pail of eggshells and coffee grounds.  Once the hole was filled, he would cover it with dirt and dig a new hole.  This mini-composting approach works well for people who don’t have room for a large compost pile and the soil helps mask odors to keep the critters away.  When doing this in winter, stockpile a five gallon bucket of soil and pre-dig the holes in the fall.  As holes are filled with compostable materials, throw some soil over the top and water everything so it freezes, keeping critter digging to a minimum.

Then there is Master Gardener CJ’s approach to composting.  CJ sends carrot peels, eggshells and other compostable materials through her food processor, along with a little water, to make a slurry.  (Keep in mind that the smaller the composting material, the quicker it decomposes.) This slurry is poured in a bucket, brown leaves are added, a trowel of soil thrown over to let the good bacteria activate the decomposition process, and repeated, layer by layer.  Storing the bucket in the garage ensured decomposition was working, even on some pretty cold days. At the end of winter, CJ had compost that was ready to use.

Manure from meat-eating animals should never be added to compost piles as diseases from these animals can transfer to humans. Turning the pile often helps the aerobic bacteria do their job more efficiently, resulting in faster composting.

Gardeners like to call compost “black gold” and rightly so since it improves soil and makes plant roots happy. Burning plant roots with excess nitrogen isn’t as much of a worry when using compost, which can happen when using manure.  Best of all, composting takes time and effort, but not really much in the way of money, so it is a great way to make your own black gold!

How to Become a Nebraska Extension Master Gardener

(Part 3 of 3)

Nebraska Extension Master Gardeners are Extension-educated volunteers who make a difference in their communities, reaching people from all backgrounds and ethnicities about research-based gardening information. Knowing lots about gardening before joining the program is not a requirement.  Becoming a Master Gardener involves a love of learning and the ability to volunteer to share gardening knowledge with others.

The first step in becoming a Master Gardener Intern is to attend an informational meeting.  This will be held Friday, January 11, 2019 at 3:00 pm at the Dodge County Extension Office, 1206 West 23rd Street in Fremont. At this no-obligation meeting you will find information on the class schedule for 2019, the number of volunteer hours required, applications to the program, and assistance in determining if this volunteer program is a good fit for you.  You will also get a chance to visit with a Master Gardener to learn of their experience in the program. Applications to the program are only available at this meeting, so if you plan to attend, please let us know you are coming by calling 402.727.2775 or emailing kcue2@unl.edu.

Master Gardener applicants are interviewed in a fun and welcoming environment.  Interns will be assigned a Master Gardener mentor to help with transitioning them through the program. Classes begin on March 6. The cost of the education is $175 and includes the Nebraska Extension Master Gardener Handbook, a t-shirt, name badge, and hand-outs.  If this fee is a challenge for you, other options will be shared at the informational meeting. 

Master Gardeners share a strong sense of fellowship and purpose, helping people in their community and county create environments that are healthy, productive and diverse.  Hope to see you at the informational meeting!

What about the Horticulture Education for Extension Master Gardeners?

(Part 2 of 3)

Nebraska Extension Master Gardeners are Extension-educated volunteers who make a difference in their communities by educating people of all backgrounds about research-based gardening information. Programs across the nation are set up on a one-for-one basis, with 1 hour of volunteer time for each hour of education received.  In Nebraska, Extension provides 40 hours of education to each Master Gardener volunteer in return for 40 hours of their volunteer service.

Not sure if you have enough gardening experience to qualify for the Master Gardener program? This isn’t an issue. Nebraska Extension closes any gardening knowledge gaps by providing research-based education. Topics covered include botany, soils, insect pests, plant diseases, weeds, turfgrass management, tree pruning and growing vegetables, plus a broad array of other gardening topics. All gardening education will be specific to the region, with updates on new/emerging problems. Instruction consists of lectures, labs and reading assignments and all classes are taught by Extension educators who are experts in their field.

Besides a world class education, Nebraska Extension Master Gardener volunteers maintain their connection to Extension through continuing education and project activities.  Most importantly, they enjoy fellowship centered on a love of gardening and sharing that enthusiasm with others.

Next: Part 3 of 3, How do I become a Nebraska Extension Master Gardener?

What are Nebraska Extension Master Gardeners?

(Part 1 of 3)

Nebraska Extension Master Gardeners are Extension-educated volunteers who make a difference in their communities, reaching people from all backgrounds and ethnicities about research-based gardening information.  While beautification of outdoor spaces is one of the happy consequences of their volunteer efforts, Master Gardeners do so much more: 

▪They work with child care centers and school programs to start youth on a journey of lifelong gardening and ensure the skills necessary to have access to fresh food. 

▪They serve as consultants to community and food pantry gardens.

▪Master Gardener volunteers work with garden clubs and school groups to foster, plant, and  maintain habitats for pollinators.

▪They answer questions from the public about gardening-related topics through local Extension offices via the horticulture helpline and “Ask the Master Gardener” tables.  

▪Master Gardeners provide gardening programs and demonstrations to clubs, senior citizen  centers, neighborhood associations, farmers markets, and youth groups.

Besides a love of gardening, Nebraska Extension Master Gardeners have good people skills and a strong appreciation for the research that goes into making everyone better gardeners, reducing waste that goes into landfills and using Integrated Pest Management as a means of solving pest problems, regardless if the pest is a plant disease, insect or weed.

Nebraska Extension Master Gardener volunteers have a long history of supporting the land grant mission to improve people’s lives by providing research-based education. The Extension Master Gardener program began in King County, Washington, in 1971 as an outreach to plug the gap between the demand for horticulture information and the shortfall of Extension staff to answer those questions.  Hippies and “getting back to Mother Earth” were two cultural dynamics leading to the increased demand.  Since that time, the Extension Master Gardener program has expanded across the United States, is in four Canadian provinces, and now South Korea, joining in 2011.

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