Cold Temperature Damage and Spring Green-Up of Warm-Season Grasses
Local warm season turf has many dead and damaged areas. Grady Miller, NC State University Crop and Soil Sciences Professor and Kaki Carl provide this look at how warm turfgrasses across the state have responded to our inconsistent temperatures this year.
The green-up of some warm-season grasses began in February and then cold temperatures in March hit hard. Early April temperatures were below normal. It was apparent by late April that warm-season grasses had been hit pretty hard from either low winter temperatures, extended periods of low temperatures, and/or early green-up in February followed by low temperatures.
Because of the conditions experienced this winter and spring, it seems that no species of warm-season turfgrass has totally escaped damage. Damage has been seen from the coast to the mountains wherever warm-season grasses are grown. Turfgrasses that were installed in 2017 (especially late in the year) were more likely to be devastated due to immaturity, but many of the damaged areas had mature turfgrass.
The most devastation has been with St. Augustinegrass in the Piedmont parts of the state including 100% winterkill of this grass in some areas. Centipedegrass in the Piedmont has also had widespread damage in some areas but seems to be greening up ok in other locations. Disease hit some centipedegrass during the green up periods that further set back some turfgrass.
Bermudagrass is normally quite tolerant to most of our winters, but there is some moderately damaged bermudagrass and in a few cases, some heavily damaged bermudagrass stands. The worst damage on bermudagrass seems to be those grasses that greened up early (February) and then were more susceptible to low temperatures in March. This resulted in some cultivars that are normally very cold temperature tolerant getting hit harder than those cultivars generally considered less cold tolerant.
This year’s zoysiagrass damage seems to have a strong relationship with its growing conditions and health status going into winter. Lawn areas that tend to stay wet and/or grasses that went into fall a bit weaker because of traffic, shade-stressed or poorly rooted, tended to have more winter damage. There are also heavy large patch areas on some zoysiagrasses this spring possibly with other factors besides just winter temperatures.
The end result for the warm-season grasses will be delayed greening and very slow fill in the “dead areas”. In some cases, re-establishment may be necessary. Warm-season grasses have the ability to fill by rhizome and/or stolon growth but if the damaged area is extensive that could take weeks to months before full density is achieved. Until there is adequate fill of turf, weeds will have a greater opportunity to come into the stand. Monitor for weeds, disease and insect pressure during the early spring through the recovery period.