Trees And Shrubs Articles

Collecting and Starting Seeds from Trees and Shrubs

Now is a great time to collect seeds from trees and shrubs to start your own and add diversity to your landscape.  If you think starting trees from seeds is a silly way to get trees into your landscape, think again.  I appreciate the story Justin Evertson of the Nebraska Statewide Arboretum likes to share about his 15-foot-tall bur oak. Justin started the tree from an acorn he planted just ten years ago. The tree was quick to establish and grow, disavowing oaks as slow-growing trees. . . read more

Final Garden Steps of the Season

As the first frost of the season becomes imminent, look around the garden for any final tasks to tidy up the garden. Harvest any warm season crops that will be damaged by frost, including tomatoes, green beans, cucumbers, basil, and zucchini.   Pumpkins, if they’ve begun turning orange, can be harvested from plants and will continue to ripen.  Food is food, so look at those things you can still take advantage of.  For instance, squash blossoms are edible and highly prized for their delicate flavor. You can harvest the blossoms for yourself or leave them in place for the pollinators to partake of that last delectable bit of nectar. . . read more

The Deepening Drought

Even with the much-appreciated recent rains, it isn’t enough water to lift the region out of drought. There are some changes we can implement to help plants while still making the most of the water we have.

What to Water
For landscape plants, priorities for watering are placed in importance: 1. Plants planted within the past 5 years, 2, Evergreens and orchards, and 3. All other plants. New trees and shrubs are watered 3-5 gallons per caliper inch (the trunk diameter in inches) per week. Evergreens and fruit trees, along with all other landscape plants, need an inch of water, applied all in one application, per week. Be aware that dwarf and semi-dwarf fruit trees should also be watered. . . . read more

Drought 2022

As much of the region deepens to severe and extreme drought, it is crucial to provide water to plants impacted by the dry conditions. Orchards, landscape plants, trees, conifers, shrubs, and windbreaks will need a deep soaking to survive the summer drought and increase chances for winter survival. . . . read more

Magnolia Scale

Now is the time to check magnolia trees in your landscape for magnolia scale, Neolecanium cornuparvum.  Unlike hard-shelled scale, this sucking pest is considered a soft scale, damaging branches and twigs by removing sap through a needle-like mouthpart. Branch stunting and death, yellowing leaves, and the development of sooty mold, which forms from the insects’ sugary excretions, called honeydew, occur from scale infestations. With severe infestations, tree death is likely.  In addition, honeydew accumulates on vehicles, sidewalks, lawns, and anything located beneath trees, making things sticky and fostering sooty mold development.  Often, it is this very thing that alerts tree owners of the presence of scale.  At times, ants, wasps, and other insects will feed on honeydew, adding to the level of activity around trees. . . read more

The Intersection of Landscape Design and Call Before You Dig

The request to the 811 center was like many received—locate the utilities because the homeowner wished to DIY a new privacy fence. Once the utilities were marked, the homeowner began to dig holes for the uprights, thinking each flag marked where he SHOULD dig, instead of where he SHOULD NOT dig. After severing the utility in multiple places, a hefty fine, and costs to reinstate the utility, the homeowner came away with a new appreciation for all that goes on below the soil surface. He was lucky because none of the damaged lines affected people or property. Things could have been worse because what goes on below ground, overhead (think electrical lines), and nearby (houses, outbuildings) all impact the projects we undertake to have safe and beautiful outdoor space. . . read more

When Plants Defend Themselves

There is a great line in the first Jurassic Park movie when Ellie, the character played by Laura Dern, says, and I’m paraphrasing here, “Plants can be pretty but will defend themselves if threatened.”  Assuredly, not all plants are sweet and accommodating. Of course, there are plants that throw in their lot with humans, giving people fruits and vegetables for food, fiber for textiles, and medicines for health. We manipulate plants to get what we need, and we aid their survival by saving seed and propagating plants.  It begs the question, though, are we manipulating plants or are they manipulating us? . . . read more

Now is the time to . . .

Put down grub control to manage grub damage in lawns. The end of June/beginning of July is the window to complete this task, when grubs are small and more easily managed. 

Stop using herbicides to manage nutsedge.  Nutsedge has tiny growths at the end of roots, called nutlets, that will begin growth when the parent plant is killed, making for even more plants. . . 

Why Lion's Tailing is Bad for Trees

Lion’s tailing to reduce wind resistance or to have enough sunlight for a thick lawn beneath trees is a detrimental practice that reduces tree structural stability. Lion’s tailing is pruning in the extreme, removing a tree’s lower canopy and inside branches, leaving just a cluster of leaves and twigs at the end of large branches. . . read more

Browning Needles of Juniper and Arborvitae

Many tree owners have been confronted with browning evergreens this spring. Even the tough-as-nails-never-needs-attention junipers are brown, in some cases entire trees. The winter of 2021-2022 showed deepening drought and this dryness, coupled with strong winds, was death to many evergreens, particularly junipers and arborvitaes. . . read more

Trees: Mulching And Pruning

As a final step in the planting process, newly-planted trees benefit from mulch. Not limited to new trees, even well-established trees benefit from cooler soils that promote root growth and nutrient and water uptake.  With the task of mulching comes added attention to the amount of mulch used. “Mulch volcanos” are the tongue-in-cheek adage used to describe the cones of mulch piled high around trunks.  Not only do these foster homes for voles, who love to eat the tender water-conducting tissues beneath bark, but mulch volcanos promote decay by rotting the base of trees. The practice has become epidemic with this “more is better” approach, fostering a new industry of arborists and landscape managers who specialize in removing mulch volcanos and properly installing mulch rings that are better suited to tree health and are characterized as “mulch donuts”.  This approach provides 2-4 inches of mulch spread over the root zone, leaving the center 3-4 inches free of mulch to allow air circulation around trunks. At a minimum, especially for new trees, the mulch ring should extend three feet out from trunks, with beds expanded as trees grow. . . . read more

Trees: Planting And Watering

Now that Spring has sprung and you’ve made your choice of what tree to plant, be sure to put as much thought and sweat equity into making sure your new tree is planted correctly.  First, locate the tree’s root flare, the natural widening found where the tree trunk meets the roots. It may be necessary to remove excess soil at the top of the rootball to locate the flare. Then measure the distance from the flare to the bottom of the rootball. Dig the planting hole to this depth, opting to make the hole wider than deep. This allows the rootball to set firmly on un-loosened soil making it less likely to sink over time, while the hole’s width allows soil to be broken up as it is backfilled. Keep your foot out of the planting hole, firming the soil instead by watering to eliminate air pockets. When finished, the tree’s flare should be visible at or slightly above the soil line. . . . read more

Tree Diversity

With Earth Day and Arbor Day coming up next month, it is a good time to talk about trees, aptly called “the lungs of the earth” for the carbon dioxide they take in and oxygen they exhale, but also for the air pollutants they mitigate.  As people plan to add trees to their landscape this year, there are some important steps to ensure successful establishment and that trees planted now survive. It is estimated it takes one to two decades before costs associated with planting new trees is recouped in savings from the benefits of shade, windbreaks, and rainwater mitigation. This is a compelling reason to make sure trees have every chance to grow and survive.  Too often, attempts to push tree growth results in dead trees. Some short-sighted attempts are planting large trees, fertilizing them, adding mulch volcanos, and watering too much.

What are the best management practices when it comes to planning for a new tree?  Let the site be the first consideration as the presence of power lines, paved surfaces, property lines, slopes, and the size of the space dictate what tree to plant. At a minimum, trees should be planted 3-4 feet away from a paved surface to prevent expanding roots from buckling the pavement. Consideration must be given to the foundations of homes, outbuildings, and other structures to make sure roots don’t cause damage and branches do not scrape siding. When determining the distance to plant from foundations, a simple rule of thumb is to divide a tree’s full-grown canopy by two, and then add 2-3 feet. Make sure trees are planted well away from utilities as sudden changes to root zones, like trenching, cause tree decline. . . . read more

March Watering

When it comes to watering during dry winters, three factors will determine if and when water should be applied to trees and shrubs.

 1. Is the ground frozen? If soil temperature is below freezing, then water uptake by tree roots will not occur.  Push the shaft of a screwdriver into the soil to help determine if the ground is frozen. If the screwdriver pushes in easily, then soil isn’t frozen and the first requirement for winter watering has been met. Read on for other factors to consider.

2. Was last fall and the present winter exceptionally dry with minimal rain or snowfall? If you answer yes, then soils are likely dry too because winds pull moisture from plants and soil.  It is a simple task to check the soil for moisture before watering. Push a finger below the mulch layer—if the soil feels moist, then the mulch is acting as a buffer to the drying winds and watering is not necessary.  When it comes to soil moisture levels, nothing benefits trees, shrubs, and perennials like a 2–4-inch layer of wood chips spread over the root zone. If the soil is dry, then a second condition has been met for winter watering. . . . read more

Late Fall Watering

Now is the time to provide a last deep soaking of the soil prior to ground freeze. This ensures tree and shrub roots can take in the water necessary to stay hydrated, helping them to overwinter better and to arrive to spring in good condition. If you’re unsure about the dryness of you soil, the screwdriver test is the simplest way to determine moisture levels. Dry soils will resist your efforts to push the screwdriver into the soil, while a moist soil will be easily penetrated by a screwdriver. 

 In order of importance, these are the plants most in need of late fall watering: 

1. Trees and shrubs planted this past growing season—plants in this category have a limited number of roots, tapping a limited amount of space.  Watering focused on these plants should be on the root ball itself and slightly beyond to catch roots where they are at. . . . read more

Mulch Volcanos

People in the business of trees have been strong advocates for proper mulching, steering people away from the ill-advised practice of mulch volcanos around trees.  Real inroads have been made, though the practice continues, evidenced by new tree plantings with the mulch overkill. When these practices are perpetrated, the assumption this is a good practice is validated and then repeated at residences and other landscapes. . . . read more

The Black Walnut Tree

Urban dwellers either praise or curse the black walnut (Juglans nigra). Some find the tree troublesome because of the nuts they drop, the juglone (a natural herbicide) secreted into the soil to kill nearby plants, and the increased number of squirrels in the neighborhood. Supporters of black walnut like the tree because it is native, well adapted to the precipitation and temperature variations of Midwest weather, is stately, grows valuable wood and nuts, and provides food for wildlife. . . . read more

Blooming Lilacs

It is not unusual for some plants to blossom out of season.  Magnolia, crabapple, lilac, and forsythia are notably spring-blooming plants, but stressful growing conditions can instigate a type of dormancy that pushes flowering to later in the season. Lilacs are a great example this year. . . . read more

Selecting Trees

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

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

Graft Union Incompatibility

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

Winter Dieback of Trees and Shrubs

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

Colorado Spruce

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

Deep Cold

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

Road Dust

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

Staking Newly Planted Trees

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

Spring Tree Care

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

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

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

Raising Awareness of Pesticide Drift

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

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

Winter Damage To Evergreens

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

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

When Ice Damages Trees

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

Landscape Fabric

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

 Here is why. 

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

Fall's Red Leaves

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

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. . . . read more

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. . . . read more

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 . . . . read more

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. . . . read more

Trees and Galls - Part 1

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. . . . read more

Tree Galls - Part 2

As mentioned in the previous garden update (Tree Galls-Part 1), galls that form on tree leaves rarely cause much in the way of tree stress. But there are also galls that form on other parts of trees. In most cases, gall formation on leaves and flowers are of little concern, while those affecting the twigs, branches and stems merit closer monitoring. . . . read more

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. . . . read more

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. . . . read more

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. . . . read more

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. . . . read more

The Dreaded Japanese Beetles 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 . . . . read more

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. . . . read more

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. . . . read more

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. . . . read more

Peach Tree Curl

Peach leaf curl is prevalent this spring.  The fungal pathogen, Taphrina deformans, causes puckering of leaves 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. . . . read more

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. . . . read more

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 . . . . read more

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. . . . read more

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. . . . read more

It's The Berries

As autumn’s colorful leaves fall to the ground, our attention turns to berries as a source of color in our landscapes and for cuttings to grace our tables and entryways.

Crabapples represent some of the most reliable of spring’s breathtaking flowers, but the fruit they produce also offer an array of yellow, orange and red in the fall.  Older crabapple varieties are notorious for fallen fruit that become a mess on sidewalks and driveways. Instead, look for varieties with persistent fruit so they stay prettily on the tree until the songbirds, like cedar waxwings, help themselves. Crabapple varieties with persistent fruit include ‘Harvest Gold’, ‘Indian Summer’, ‘Centurion’ and ‘Christmas Holly’, among others. . . . read more

Leaf Colors of Autumn

This season’s autumn colors have been exceptional. Shortened day lengths, sunny and warm days, cool nights, and adequate soil moisture provide the perfect conditions to showcase autumn’s greens, golds, reds, oranges and coppers in our trees and shrubs.  Fall leaf color is a dynamic process, influenced by the decline and production of pigments within leaves.  It isn’t unusual for leaf colors to fluctuate throughout fall or to have a myriad of colors at the same time on one tree. . . . read more

The Benefits of Fallen Leaves

It’s too bad autumn’s fallen leaves are seen as a nuisance, something to be gotten rid of as soon as possible. In truth, they are a boon to landscapes, serving as mulches, benefiting soils, and boosting our compost piles. Not only are leaf piles fun to jump in and make for great leaf fights, by using leaves, we keep this resource out of landfills.

Mulching leaves into the turfgrass with the mower is one easy option.  The ideal amount of leaf mulch is enough so that bits of leaves filter between the blades of grass.  More than this can suffocate the turf, contributing to snow mold damage over the winter months.  With my electric mower, I can start the engine while the mower deck is directly over the pile.  This makes quick work of a large pile into a usable mulch.  A leaf blower with a vacuum/mulching function does equally well, allowing for the bagging of mulched leaves to use elsewhere. . . . read more

So Emerald Ash Borer Has Been Found In My Area - Now What?

Last week’s finding of the emerald ash borer (EAB) west of Fremont has ash tree owners wondering what to do next.  There are several options but first it’s helpful to know if your ash tree lies within a 15 mile radius. What is the importance of knowing if your ash lies within this radius, you ask?  Treatments stress trees, which is justifiable if EAB is imminent, but not so much if EAB is far away. . . . read more

Iron Chlorosis

Pin oak and river birch are trees that can suffer from iron chlorosis, a condition of yellow leaves due to a lack of sufficient iron in the plant.  Iron is necessary for good plant health and soils in this area have sufficient iron in the soil.  The glitch comes in when the soil’s pH (the measure of a soil’s acidity or alkalinity) is high.  Iron becomes limited at a pH of 7.5 and higher because the soil is “holding on” to the iron, making it unavailable for uptake by tree roots. . . . read more

Leaf Scorch of Trees and Shrubs

Brown leaves on trees and shrubs can be indicators of leaf scorch.  Leaf scorch occurs during hot weather when the rate of water uptake by roots is exceeded by the rate of water loss from leaves.    Plants respond to rapid water loss by willingly letting some leaves die back so that water intake equals the amount of water loss.   Not all trees have the same level of leaf dieback—it varies from tree to tree, by circumstance and by species. . . . read more

Leaf Scorch

Leaf scorch, also called sunscald, is the bronzing of leaf surfaces and crisping of leaf edges.  Even plants that are well-adapted to our climate can be scorched.  Plants have amazing resiliency, especially when Mother Nature eases them into changing seasons.  But taking into consideration a spring like this one—cold and rainy—with an abrupt change to record heat, then scorched plants are to be expected. . . . read more

Japanese Beetles - They're Colorful, They're Hungry and They're Here

The most important thing to understand about Japanese beetles is their feeding doesn’t kill trees, shrubs and flowers.  Granted, it isn’t fun to see the lacy leaves they’ve created, but pesticide management options require thought and planning before you set out for revenge.

Systemic insecticides, for instance those containing the active ingredient imidacloprid, are taken in by plant tissues.  Systemics may have a label for application to trees and shrubs but before these are used, the applicator should make sure the plant is past its flowering stage in order to protect pollinators. Also, a systemic product can never be used on linden trees. . . . read more

Maple Bladder Galls

If you have a sliver or red maple tree, you’ve most likely noticed small raised bumps on the leaves.  Tree owners will call them “freckles”, “measles” and sometimes even “zits”.  Whatever they are called, maple bladder galls are caused by a very tiny mite.  The galls themselves are made up of plant tissue and are a part of the leaf.  Maple bladder gall mites live, eat and mate inside the galls and are well-protected from any application of a miticide. . . . read more

Raised Beds around Trees - A Bad Idea for Landscapes

As we plan for our much anticipated outdoor projects this gardening season, let’s discuss the tree-killing practice of building raised beds around trees.  Don’t get me wrong here—I am not talking about planting hosta beneath a tree, I’m talking about building a RAISED bed around a tree. This unfortunate practice leads to many dead trees, often years later when the tree owner no longer connects the tree dying with the creation of the raised bed. . . . read more

Mulch Volcanoes - Compromising Tree Health

You’ve seen this before—mulch piled so high around a tree that it resembles a volcano with a stick coming out of the center.  So goes the plight of trees trying to survive under such conditions.  Despite the research indicating how bad this is for trees, we see it time and again. . . . read more

Japanese Beetles

With over 300 ornamental and edible plants they like to feed on, Japanese beetles (JB) can quickly become an overwhelming insect in the landscape.  Last year, one gardener brought in his peach so covered in Japanese beetles that it was hard to identify the fruit as a peach! . . . read more

Emerald Ash Borer

The much-dreaded emerald ash borer (EAB) was identified in Douglas County in 2016.  Since that time, EAB has been found in several other locations that holds implications for counties in the eastern part of Nebraska.

Infestations of this insect are known to kill ash trees in a relatively short time period—from 3 to 5 years in most cases.  Once an ash tree is dead, the tree quickly becomes brittle and is a threat to nearby homes, vehicles, and yes, people. . . . read more

Heavy Rainfall, Strong Winds, High Humidity

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

Vegetable Plants

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

Trees and Shrubs

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

Lawns

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