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Tag: winter injury

Thinking Ahead to Factors that Can Impact Freeze Injury of Warm-Season Grasses

Posted on by Jack Fry

 

Winter injury in certain areas where warm-season grasses grow in the transition zone is not unusual.  Specifically, here are the things that can have a significant impact on winter injury of zoysiagrass and bermudagrass:

 

 

 

  • Selection of a less cold hardy warm-season grass: There is a relatively short list of bermudgrass and zoysiagrass cultivars that are best adopted to the transition zone, including Kansas. Here are a few of each of those species that are relatively good through winter, but that doesn’t mean they can’t suffer winter injury:

Zoysiagrass – Meyer, Innovation, Zenith (seeded), Chisholm

Bermudagrass – Tahoma 31, Latitude 36, Northbridge, Yukon (seeded), Monaco (seeded)

 

  • High Nitrogen levels: High levels of nitrogen fertilizer through the growing season, or nitrogen applied in the fall can have a more significant impact on winter injury.

 

  • Shade: Shade reduces photosynthesis and carbohydrate production by grasses, and can significantly reduce the potential for a species/cultivar to survive cold temperatures.  Trimming trees or removing them may be required to enhance cold hardiness.

 

  • Traffic: Significant traffic on the soil and turf prior to winter can have a significant impact on the turf and result in higher levels of winter injury.  Traffic control (not allowing excessive traffic) and effective aerification can help enhance its survival.

 

  • Excessively wet soil: It’s not unusual for warm-season turf that sits in a low area (often on golf course fairways) where water accumulates can have a greater impact of winter injury.  High levels of water in the soil will impact these grasses when severe cold arrives.  Improved drainage can help protect these areas.

 

  • Lack of snow cover: Snow is very beneficial to protect warm-season grasses prior to excessively low temperatures.  For example, several years ago we had snow cover in Olathe, KS when temperatures were at least -15 F and no winter injury occurred.

 

  • Grass not fully acclimated for cold temperatures: There is a greater chance of freezing injury if temperatures get quite low when the grass had not fully acclimated to cold. Example – excessively low temperatures in November or December can have a significant impact.  Likewise, the same may occur during late winter or early spring when warmth approaches and then that is followed by excessive cold.

 

  • Exposure to wind on high level areas: This can often cause desiccation in winter if exposed to strong wind when there is no snow cover.  If expected in the near future, it may be useful to apply water on these elevated areas before the excessive cold arrives.  Or…some type of cover to protect the surface.

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/

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

 

Winter Desiccation

Posted on by Jack Fry
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

Cover Your Crowns

Posted on by Jack Fry
Some grasses, such as bermuda, are susceptible to winter injury when crowns become elevated.

There are various ways to keep crowns covered, some are more practical than others.  One excellent cover is snow.   In 2021, air temperatures in Kansas reached -18 F in the eastern part of the state and low temperature extremes occurred in southern states too.  For example, parts of southern Texas reached temperatures as low as 5 F in mid-February.  A municipal park manager in southern Kansas had sodded Latitude 36 bermudagrass, a cultivar with good cold hardiness, on baseball fields and dog parks in late summer 2020 and was quite concerned about its survival following the February temperature plunge.  When April arrived in our state, I visited the location to investigate the extent of winterkill, but it was minimal.  About 4 inches of snow helped insulate the crowns.  In other areas of the transition zone and upper South that had no snow cover, some extensive winterkill of bermudagrass and other warm-season grasses occurred.

There are other, more reliable ways to protect the crowns of warm-season grasses, as snow may not always be present when temperatures like this happen.  Soil provides a warm blanket for crowns.  When air temperatures drop below 0 F, it is common for temperatures just below the soil surface to be significantly higher.  In Kansas in Februrary, 2021, lowest soil temperatures at a 2 inch depth were generally at least 40 F warmer than the lowest air temperature that occurred (e.g. air at -18F, soil at about 25 F).  Soil provides a very nice blanket for crowns. It confirms that keeping crowns from rising above the soil by minimizing thatch accumulation is important, and removing thatch may be needed if it becomes excessive.  For crowns that are above the surface, topdressing will help create a warmer environment during winter.

Keep ’em covered!