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K-State Turf and Landscape Blog

Category: Environment

Ice, Ice Baby

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

Pushing Snow

Many of you are busy “pushing snow” with the recent cold weather, and there will likely be more snow to push in the next couple of months. Please take a few minutes to train your staff on protecting ornamental plants when clearing hard surfaces like parking lots.

While clearing the lot, driveway, or sidewalk is the most critical objective, “do no harm” should also be a goal. Far too many plants are crushed by the push and weight of snow in winter months. Sometimes, the mystery summer problem is actually a clear winter problem.

There is a tendency to pile snow on top of green spaces in parking lots. However, plants in those spaces continue to need to photosynthesize (evergreens) and exchange gases and are likely to die or suffer severe dieback if the cold weather persists and the snow takes a significant time to melt. Piling snow in planting areas can also contribute to soil compaction and root decline, causing problems later in the growing season.

De-icing chemicals are often mixed into snow that is pushed into landscape settings. As the snow melts, it dumps salt into the planting area, damaging shoots and roots for the long term. To minimize the landscape impacts of clearing snow, consider alternative de-icing salts like calcium chloride and calcium magnesium acetate and follow the label instructions when possible. Sand can also help provide traction.

With your staff, practice identifying an appropriate place to pile snow that isn’t in landscape areas, offers a place to collect runoff, and won’t result in slush that can splash onto plants. When possible, make these decisions before snow is on the ground—snow can cover a lot of detail and make it easy to lose track of the areas that need to be preserved.

Study each site individually and develop a plan for human, pet, and plant safety when winter storms hit to avoid problems in the future and establish trust with your clients.

Cool Fall Weather = Large Patch Season

By Megan Kennelly, Professor, Turfgrass Disease Management & Development

Here in Kansas we see our most severe large patch symptoms in spring, but we can see it in fall, especially if conditions are cool and wet. Here, also, we’ve had pretty good success at suppressing spring symptoms with applications the prior fall.

We at KSU and others have been busy trying to tackle this disease in recent years, especially with the increasing interest in zoysia. For a review of research across the transition zone you can check out this article in Golfdom:

Don’t get overmatched: Dispatch that large patch

Summary of Extreme Temperatures

By Megan Kennelly, KSU Dept of Plant Pathology

We have all been feeling the heat lately. I hope everyone has been staying safe and hydrated.

Just how hot has it been? The KSU Mesonet weather team provides a helpful summary here with interesting perspectives and historical context:

https://eupdate.agronomy.ksu.edu/article_new/a-hot-day-for-the-record-books-in-kansas-august-19-2023-559-8

 

 

Here is one of their maps – click the above link for additional data and figures. Source: Kansas Mesonet https://mesonet.k-state.edu/

Bermudagrass Green Up in March?

 

Children’s Mercy Park in Kansas City, KS is quite unique.  Northbridge  bermudagrass comprises the soccer field used for Sporting KC, and the first home game is on March 11th.  In the past, it has been typical for those hosting games in early spring, on which bermudagrass is the focus, to overseed with a cool-season grass, such as perennial ryegrass in the fall.  This enhances fall and spring color and helps protect the underlying bermudagrass.  However, overseeding with perennial ryegrass also results in significant competition for the bermudagrass to succeed.  Children’s Mercy Park had a different strategy for enhancing early spring color and promoting growth during cool weather.

How is it that bermudagrass is fully green in Kansas in February? Casey Montgomery, Director of Turf Operations for Sporting KC, had a subsurface heat system installed in the field.  The heat is produced through electricity – ribbons are buried at 8 inches deep and run 6 inches apart through the field.  From late autumn until early February, soil temperature will be at 50 F (at 8 inch depth).  Temperature is increased to 70+ F starting in February.

 

Casey Montgomery, MU alum and turf specialist for Sporting KC, has taken a very unique approach to encourage early bermudagrass green up.

 

Seeing green bermudagrass in KS in March is not common (unless in a greenhouse!).

 

 

 

 

 

 

 

 

 

 

 

 

 

In addition, the field is frequently covered when necessary, and also receives “grow lights” to enhance photosynthesis in early spring.  All of these are impressive strategies for stimulating growth and health of bermudagrass.  However, soil heating systems and supplemental lighting aren’t factors that most managers overseeing bermudagrass sporting fields would be able to include in their operating budget.  This unique approach in enhancing bermudagrass green up and growth on professional sports turf is quite impressive!

 

 

 

Enhancing Spring Green Up

Several things can result in earlier spring green up of cool-season grasses in March.  Here are a few thoughts:

  • In general, Kentucky bluegrass tends to green up faster than tall fescue – species selection can make a difference.
  • Good nitrogen fertilization in autumn enhances spring green up.  More details on fertilizer strategies and how they affect growth are HERE.
  • Grasses growing close to concrete will exhibit faster spring green up (photo below).  In addition, if traffic has thinned turf, it may green up faster as well, as sunlight warms the soil surface in that area.  Note – installing concrete and imposing traffic are not recommended just to enhance green up!

    Grasses growing close to concrete experience warmer conditions and green up early. Turf exposed to traffic that is thinner also greens up fast.
  • Mowing low in early spring will enhance green up.  Tall grass intercepts sunlight (photo below).  By cutting the canopy lower, more light reaches the surface and the soil warms more quickly.  In addition, you’re also removing that portion of leaves that has exhibited necrosis (browning) due to cold winter weather – new emerging leaves will then be visible sooner.

    Tall fescue mowed at about 1 inch (in circle) in February is greening up faster than that still mowed at 2-3 inches.
  • If low mowing continues through the spring or turf is thin near concrete, expect weed emergence to happen sooner (e.g., crabgrass emergence).  This would require timely application of herbicides.

 

 

 

Watering Landscape Ornamentals

By Dr. Cheryl Boyer

It’s that time of the year when it’s both very hot and, likely, very dry. While it’s important to water landscape ornamentals all year long, now is a critical time to make sure plants have all the resources they need.

We have several publications about best practices for watering:

Newly planted trees (within their first year) should be watered at least weekly but check the soil to make sure it’s draining well. Slow-release watering methods like micro-pore bags and 5-gallon buckets with small (1/8-inch) drainage holes are a good way to apply irrigation to trees and some shrubs. However, remember to remove the bags when they are empty to ensure good airflow around plant stems and reduce pests and diseases. Removing turfgrass and other ornamental plants to at least the tree dripline (or beyond) will help trees access more water and grow more quickly—make sure to mulch the turfgrass-free zone to help retain applied water.

Established trees will benefit from a thorough soaking (to a depth of 12 inches out to and beyond the drip line) every 3 to 4 weeks. Established shrubs need water every 2 to 3 weeks during this drought- and heat-prone time of year. Plants growing in raised beds and berms may need to be watered every 1 to 2 weeks. Soaker hoses work well for watering established trees and shrubs.

You may want to consider taking advantage of a light rainfall (if you get one in July and August) by watering immediately afterward to help moisture move deeper into the root zone.

Any way you slice it, watering is a good thing. There are many other factors to consider for successful planting, but right now watering is top of the list. Keep it up—plants are thirsty just like you!

It is time to…..WATER, WATER, WATER!

By Brooke Garcia

The temperatures are reaching summer high’s this week, and it is more important than ever to be monitoring and increasing watering schedules. Adjusting irrigation settings to accomodate for extreme temperatures will be vital for the health and survival of new plantings, as well as established plantings.

Featured in the Horticulture e-Newsletter, Ward Upham discussed the importance of watering for trees and shurbs. The article is featured in the link here.

Here are some other timely blog posts about watering as well:

New Publication: Industrial Weed Control

By Brooke Garcia

Visit the KSRE Bookstore to view the updated publication on Industrial Weed Control, which has a focus on right-of-way and industrial areas. This publication will describe how to manage weeds in the following areas:

  • near or around buildings
  • roads and roadsides
  • industrial sites and areas

“Excess vegetation can obstruct road visibility, create fire hazards, impair drainage, and reduce the useful life of structures. Reliability and public safety across rights-of-way and industrial areas require controlling unwanted vegetation.”  ~ Frannie Miller & Sarah Lancaster 

Get the PDF copy of the publication here: Industrial Weed Control