Kansas State University

search

K-State Turf and Landscape Blog

Author: Teresa Roberts

Mulch Rings Around Trees in Turfgrass

Posted on by Teresa Roberts

By Cody Domenghini, Assistant Professor, Landscape Management

A mulch ring is a circular border surrounding a tree commonly made of organic material such as wood chips. Trees planted in turfgrass should have mulch rings installed around them for a couple of reasons. Creating a mulch boundary around trees prevents lawn maintenance equipment such as string trimmers and mowers from getting too close to the trunk and causing damage. When grass is allowed to grow right up to the trunk the tree roots are in competition with the turfgrass for water and nutrients. A mulch layer over the root zone eliminates this conflict.

Ideally, trees should be planted in a landscape bed rather than in the middle of a lawn. However, when grown in a lawn, trees should have a mulch ring at least three feet in diameter for every inch of tree trunk caliper surrounding them.

Measuring tree trunk caliper of a young tree planted in turfgrass.

The mulch should resemble the shape of a donut with the center of the ring creating a 4-6” gap between the trunk of the tree and the start of the mulch. The space between the tree trunk and the mulch ring allows oxygen and water to easily reach the roots and prevents the risk of rot at the base of the trunk.

Example of a donut shaped mulch ring with the mulch not touching the tree trunk.
Volcano mulching

Avoid the common mistake of “volcano mulching”. Layer the mulch 2-4” deep. Throughout the year the mulch will breakdown, contributing organic matter to the soil and improving soil quality. Mulch should be reapplied annually. When adding a tree ring to an already established tree in a lawn, carefully remove the sod from the top few inches to not damage any tree roots.

Adding a mulch ring to an established tree.

Mulch rings for large trees should be large enough to create a barrier between the edge of the turfgrass and the trunk of the tree to prevent damage to the trunk from mowing equipment, but do not necessarily have to follow the size guidelines advised for younger trees. Adding tree rings and mulch around trees is best done in the spring, but can be completed anytime of the year.

Below is a link to an extension article discussing the proper way to mulch trees.

https://www.johnson.k-state.edu/lawn-garden/agent-articles/trees-shrubs/how-to-mulch-trees.html

Join us at the 2024 Kansas Turf & Ornamentals Field Day

Posted on by Teresa Roberts

Come join us at Kansas Turf & Ornamentals Field Day, held Thursday, August 1, 2024.

Held at Rocky Ford Turf Research Center, 1700 Barnes Rd, Manhattan, KS, this program is designed for all segments of the turf and ornamentals industry – lawn care, athletic fields, golf courses, landscape, nursery, and grounds maintenance.

Included on the program are research presentations, problem diagnosis, commercial exhibits and equipment displays. There will be time to see current research, talk to experts, and get the answers to your questions.

The tour qualifies for one hour of pesticide recertification credit in both 3A and 3B are available, as well as .25 GCSAA education points.

You can find more information about each tour and how to register at:
https://www.k-state.edu/turf/events/index.html

Please register by July 24…we hope to see you there!

If you are interested in serving as a lunch sponsor or vendor for the event, contact Christy Dipman at 785-532-6173 or cdipman@ksu.edu.

Now is the Time to Scout for Bagworms

Posted on by Teresa Roberts

Article derived from KSRE News Story: Now is the Time to Scout for Bagworms

Patience and persistence is key when trying to manage bagworms. Begin scouting in early May, and depending on weather conditions – through early summer.

Once caterpillars emerge, they begin feeding on the host tree or shrub, creating their protective bags. In addition to emergence over time, young bagworms can ‘blow in’ – called ‘ballooning’ – from neighboring plants on silken threads, which increases the importance of treating multiple times during the growing season. Watch both conifers and deciduous trees and shrubs. Although defoliation of deciduous trees and shrubs don’t typically affect long-term health of trees and shrubs, extreme defoliation of conifers can cause stress or kill conifers outright.

Bagworm feeding on plant foliage, photo by Raymond Cloyd

Hand removing and destroying bagworm bags is an option for smaller infestations. For larger infestations, the bag provides protection from insecticide treatments, so it’s important to apply applications when the bagworms are young. Apply insecticides weekly when young bagworms are present, up to 5 weeks. Treat windbreaks, Christmas trees, and ornamental landscape trees as soon as bagworms are present to prevent bagworms from causing substantial plant damage. Thorough coverage is important, including penetration into the interior plant canopy and upper branches.

Bagworm bags hanging from a tree branch, photo by Raymond Cloyd

Many insecticides are labeled for bagworms, but timing of application and thorough coverage will ensure the effectiveness of insecticides in managing bagworms. When bagworm caterpillars are small (1/8 to 1/4 of an inch long), products containing Bacillus thuringiensis subspecies kurstaki (Btk) or spinosad as the active ingredient can be effective. These insecticides have minimal direct impact on beneficial insects compared to broad-spectrum insecticides, which could lead to outbreaks of spider mites or scale insects that can cause damage to treated trees and shrubs.

If insecticides are not applied when bagworm caterpillars are small (1/8 to 1/4 of an inch in length) then broad-spectrum insecticides, including those containing malathion, acephate, or cyfluthrin as the active ingredients can be applied. Be sure to read the product label and follow directions.

For more information on controlling bagworms, reference the publication, Bagworm: Insect Pest of Trees and Shrubs, written by Dr. Raymond Cloyd.

Importance of Turf Selection

Posted on by Teresa Roberts

Adapted from the K-State Turf and Landscape Problem Solver

Careful turfgrass selection is an important first step in establishing, overseeding, or renovating a turfgrass. Many potential problems related to turf use, appearance, environment, insect or disease pests, and cultural practices can be avoided by properly choosing species and cultivars that best fit the situation in which the turfgrass will be grown.  A turfgrass, when planted in areas where it is not adapted, often deteriorates or fails. The result of planting a turfgrass where it is not adapted is a poor-quality turf that requires excessive pesticide applications, fertilization, and replanting to retain a green ground cover. A high-quality turf may not be obtainable in this situation.

Consider these criteria when selecting a turfgrass:

  • Desired quality
  • Appearance – turf color, texture, density, growth habit, and uniformity
  • Use – turf purpose, e. g., athletic or play surface, lawn, erosion control
  • Pest resistance – turf resistance or tolerance to disease or insect pests
  • Culture – turf management requirements from a time and a financial view point
  • Site – turf soil and sunlight requirements compared to those of the final planting site.

Turfgrasses differ with regard to these criteria. For example, some Kentucky bluegrass cultivars form a dark emerald green turf adapted to high maintenance and light shade. This can be contrasted with buffalograss, a gray-green, low-maintenance turfgrass that performs poorly in light shade. Other differences among species and cultivars also exist regarding wear tolerance, environmental adaptation, pest resistance, and cultural requirements. Careful selection at planting time is the best way to solve potential problems in the future.

Generally, the cost of planting turfgrasses, whether from seed, sod, plugs, sprigs, or stolons, should be of minimal concern. In most normal plantings, the cost difference between poor-quality and high-quality seed or vegetative propagules is small, and the time and money spent trying to produce high-quality turf from low-quality seed or vegetative material can often become great. The long-term benefit of planting high-quality turfgrasses in appropriate conditions is a healthy, cost-effective, quality turf.

The effort and time expended selecting the right grass species, mixes, and/or blends will be well spent. Consider the site, use, desired appearance, and management the turf will receive when selecting the species combination. Then select cultivars that best fulfill the desired outcome. Often, there may be more than one “good fit” between turf species, mixes, and/or blends for the specific situation. In such cases, cost and availability may become important factors in the final decision. Plant only high-quality propagules (e. g., seed, sod, plugs). When these steps are followed and the actual turf is planted, many potential problems will be reduced, or in the best of situations, eliminated.

2024 Turf and Ornamentals Field Day

Posted on by Teresa Roberts

Join us at the Kansas Turf & Ornamentals Field Day, held Thursday, August 1, 2024, at Rocky Ford Turf Research Center, 1700 Barnes Rd, Manhattan, KS.

The field day program is designed for all segments of the turf and ornamentals industry – lawn care, athletic fields, golf courses, landscape, nursery, and grounds maintenance. Included on the program are research presentations, problem diagnosis, commercial exhibits and equipment displays. There will be time to see current research, talk to experts, and get the answers to your questions.

One hour of pesticide recertification credit in both 3A and 3B are available, as well as GCSAA education points.

You can find more information and register online at:
https://www.k-state.edu/turf/events/index.html

Please register by July 26.

For questions, contact Christy Dipman at 785-532-6173 or cdipman@ksu.edu.

Pine Problems in Kansas

Posted on by Teresa Roberts

By Judy O’Mara, Diagnostician, K-State Plant Disease Diagnostic Lab

It was pretty cold in mid-January 2024, the low temps in January sent me to the K-State Mesonet (https://mesonet.k-state.edu/weather/historical/) to take a closer look at the weather patterns during that time period. The Mesonet is a collection of weather stations across Kansas that can be used in a variety of ways but my favorite is to take a look BACK in TIME at the historical weather patterns. The temperature dropped pretty low on Jan 14th (-10.5F) and Jan 15th (-10.6F) in Manhattan, KS. Brrr.

In any given year, it is not uncommon to see extreme weather patterns impact plant growth and health. Winter damage to pine trees frequently shows up on the north or northwest side of the tree, although it can hit the top of the tree as well. Winter damage can hit multiple trees or can show up on scattered trees within a planting. The outer needles tend to be scorched with the inner needle growth remaining green. The more exposed foliage is more susceptible to desiccating winter winds. Winter damage on pine trees can be confused with some common Kansas pine diseases such as pine wilt, Diplodia pine tip blight and Dothistroma needle blight.  One tip that can help to differentiate between these problems is the TIMING of the damage. Pine trees generally enter the winter looking good and then get hit by low temperatures and/or desiccating winds sometime between December-February. A look at the K-State Mesonet can help pinpoint the weather event that caused the damage.

Winter damage can look pretty dramatic but it is best to wait until early to mid-May to assess recovery potential. Even though the pine needles are scorched, the dormant buds frequently escape damage and push out new growth in the spring. The damaged needles eventually shed and the overall appearance of the tree will gradually improve. Another quick way to check recovery potential is to pop off a few buds at the end of the branch and see if they are still green inside.

Winter damage can be confused with some common Kansas pine diseases. For help sorting out these problems reach out to your local county extension office. The K-State Plant Disease Diagnostic Lab can also provide assistance.  https://www.plantpath.k-state.edu/extension/plant-disease-diagnostic-lab/

Tree and Shrub Problems in Kansas Publication Updated

Posted on by Teresa Roberts

A new version of the Tree and Shrub Problems in Kansas: Diseases, Insects, and Environmental Stresses book is now online! This guide provides an overview of different tree problems followed by an extensive itemized list of specific diseases, insects, mites, and environmental/abiotic stress problems of trees and shrubs common in Kansas, information on how to identify those problems, and guidelines for management.

https://bookstore.ksre.ksu.edu/Item.aspx?catId=538&pubId=17559

 

Planting Buffalograss and Controlling Weeds

Posted on by Teresa Roberts

By PhD student Dani McFadden, and Jack Fry, Professor and Commercial Turf Extension Specialist

Are you thinking about converting an area to buffalograss? It is a warm-season grass native to Kansas and much of the Midwest, with excellent heat, drought, and cold tolerance.  It is important to understand the characteristics of your site before determining if buffalograss is an adequate fit. Buffalograss grows best in an area receiving morning sun, and 6-8 hours of sunlight throughout each day. It is recommended to not plant buffalograss in poorly-drained areas or sandy soils. For non-irrigated sites, planting is recommended in the spring once soil temperatures reach 55 F. An optimum seeding rate is is 1.5 to 2 lbs of buffalograss burrs (1 to 5 seeds in a burr) per 1,000 sq. ft.

Buffalograss is dioecious, which means there are male and female plants.  In seeded areas, you can see the inflorescences (male flowers) on male plants  emerge several inches tall.  The female plant produces a flower close the soil and is not as noticeable.  Ultimately, several seeds are produced within the female burr. There are vegetative buffalograss cultivars that can be purchased which are most typically plugged for establishment.  They are generally the female plants (no visible seedheads during the growing season).

You can learn more about cultivars, establishment, and management by using these links:

K-State “Buffalograss Lawns”: https://bookstore.ksre.ksu.edu/pubs/mf658.pdf

K-State Turf and Landscape Blog:  https://blogs.k-state.edu/turf/

National Turf Evaluation Program:  https://ntep.org/

For irrigated sites, you can delay seeding until June through July; early June planting enhances the potential for good coverage by the end of the growing season. Seed should have good contact with the soil – planting 0.25 to 0.5 inches below the soil surface is recommended.  For effective grow-in, any non-desired vegetative grasses or weeds should be removed from the area with the use of herbicides (check label to confirm time required before seeding can be done after application).

Converting an area to buffalograss can be costly and time consuming; therefore, it is important to protect the area from weed invasion. Weed control is critical during establishment, as many weeds are able to outcompete buffalograss seedlings. Mesotrione (Tenacity) is labeled for application at the time of seeding. Quinclorac (Drive XLR8) is also labeled for application any time before or after seeding buffalograss for the postemergence control of grassy weeds. Two combination products, SquareOne and Solitare, are labeled for use on established buffalograss for the control of a broad spectrum of weeds. If you are facing weed pressure, it is important to first identify the weed before purchasing the herbicide. For example, products containing quinclorac as a single active ingredient will control many grassy weeds, with minimal control of broadleaf weeds. You should always read the herbicide label for a detailed list of weeds controlled by the product, along with application rates and timings.

 

Winter Desiccation

Posted on by Teresa Roberts

By Dr. Jack Fry, Professor and Commercial Turf Extension Specialist

Winter desiccation on a creeping bentgrass green that had significant thatch accumulation.

Winter desiccation is a form of “winter injury” that can often occur in February and March during extended periods of dry weather. Most susceptible are seedlings that were seeded late in autumn, and established turf that has excessive thatch. If you seeded in late October and turf is not yet mature, consider applying water if we get into an extended dry period.  Lack of maturity means limited root growth and more frequent water is needed.

Creeping bentgrass is quite susceptible to desiccation, particularly when it accumulates some thatch.  In fact, winter desiccation injury often more common on fairway height turf that has accumulated thatch compared to that growing on putting greens.  Roots become elevated in the thatch and are unable to absorb water from soil.  Creeping bentgrass growing on elevated sites that are most exposed to wind is most susceptible.  Again, water application may be needed during extended dry periods to reduce the risk of desiccation.  This may required methods of water application other than just irrigation.  For example, sometimes boom sprayers are used to deliver water – multiple passes may be needed.  In areas where desiccation is common on bentgrass greens, it not unusual for superintendents to topdress heavily in the fall, or provide some kind of cover on the surface through winter – sometimes synthetic cover or using branches from cedar trees or other evergreens –  to help reduce wind effects.  Click links below for more information.

USGA article

Sportsfield Management article

 

Ice, Ice Baby

Posted on by Teresa Roberts

By Dr. Jack Fry, Professor and Turf Extension Specialist

Ice can cause many problems for turf, in various forms.

Ice Inside the Plant

Ice routinely forms inside plants when temperatures drop below freezing. Where the ice forms is important – when it’s outside the plant cells, it’s usually not an issue. This is called extracellular freezing.  However, no plant cell will survive when ice forms inside it.

The most important part of the turfgrass plant regarding survival is the crown, or growing point. Again, ice forming outside cells inside the crown is common and usually not harmful. It can become an issue, primarily in warm-season grasses, like bermudagrass, when temperatures are very cold for extended periods of time. This forces water inside cells to exit toward the ice (a matter of physics), and too much water leaving the cells will cause dehydration, which can cause the crown to die.

Freezing injury on bermuda is caused by ice forming outside cells within the crown of the plant that causes dehydration.

Ice formation inside cells of the crown commonly causes the death of grasses in the northern U.S, and it’s called intracellular freezing or crown hydration injury.  Usually, grasses that succumb to this type of injury become well hydrated in early spring, often growing in low areas that don’t drain well. Hydrated crowns that are then subjected to extremely low temperatures often suffer from ice formation inside cells of the crown;  when this occurs, they don’t survive. This is common in the northern U.S. on annual bluegrass on golf greens. It could also occur here, but would be most likely on warm-season grasses lying in low areas.

Ice Covering the Plant

Fortunately, in the central U.S., we don’t deal with extended periods of ice cover on turf. Ice cover can result from sleet, freezing rain, or snow melting and refreezing. Turf managers in the northern U.S. begin to worry about ice cover when it remains in place for about 60 days. That’s usually the limit for annual bluegrass – being under ice cover more than that can cause issues with lack of oxygen and/or accumulation of toxic gases under the ice

Ice on the Leaf Surface – Frost!

In a humid environment, when the leaf surfaces cool to temperatures below freezing, ice will form as frost on the leaves. Leaves of cool-season grasses tolerate frost on leaves just fine. Leaves of warm-season grasses don’t like frost, and we often see them go dormant shortly after the first hard frost in the fall.

Frost on the leaf surface can damage when foot or vehicle traffic causes the crystals to puncture the leaf cells (photo courtesy of Dr. Hoyle).

Frost is primarily a problem for turf managers in spring and fall on cool-season grasses. Foot or vehicle traffic pushes the ice crystals through the leaf surface and punctures cells, causing them to collapse. The result is that there is often brown turf where traffic was present. Honestly, I don’t think we know enough about the physics of ice that comprises frost, and I suspect that frost differs a lot – some ice forming on leaves may be more damaging than other ice.

Following are a few articles related to frost on turf.

For golfers:

https://www.usga.org/content/usga/home-page/articles/2018/01/5-things-to-know–frost-delays.html

For superintendents managing golf courses:

https://www.golfcourseindustry.com/article/golf-frost-delay

Apparently, in Japan, golfers play year-round regardless of temperature.  Some courses ignore frost to sustain income and have had less damage than expected:

https://www.blog.asianturfgrass.com/2016/12/how-to-lose-120-million-yen-with-frost-delays.html