Green-up of some warm-season grasses ramped up with unusually high March temperatures (third warmest March since 1887). As normal, warm-season grasses growing in the shade lagged behind those growing in full sun. Then we had a cold snap (32°F in Raleigh on 9 April) that set back warm-season grasses. Those temperatures were damaging in some areas, with patches of winterkill evident.
Then the strong winds and low humidity combined with little to no spring rainfall just when the warm-season grasses started to recover from the cool temperatures. Without adequate rainfall, there has been subsequent damage to more areas. May brought some limited rainfall for some areas, but the rainfall was limited and has not continued, resulting in stressed turfgrasses throughout the state.
The US Drought Monitor of North Carolina (North Carolina drought map) currently has the entire state in some level of drought. About two-thirds is categorized in D3 -Extreme Drought. These conditions have brought about mandatory and voluntary outdoor water restrictions for several towns across the state. The weather forecast for the last couple of weeks in May looks dry and hot, which is not a good place to be moving into June.
High temperatures cause cool-season grasses like tall fescue to photorespire. This results in a heavy energy toll and additional stress on the plant. Heat alone is generally not problematic with warm-season turfgrasses unless there is low soil moisture.
Common recommendations indicate that turf this time of year needs approximately 1 inch of water per week from irrigation or rainfall. This is an approximate amount to irrigate if you want to keep the turfgrass green and growing. Turfgrass can survive under far less water, and it is recommended that conservation practices be implemented. If you decide to minimally water, then use ½ inch of water every three weeks to keep the turf crowns hydrated. This amount will not turn the turf green, but it will increase its chance of survival. Avoid herbicides and fertilizers until rains resume. Also, most water restrictions allow hand watering, so you may target areas that show visual signs of severe moisture stress.
Hopefully, the state will have more frequent rainfall in the coming weeks to months. If not, re-establishment may be necessary for cool-season turfgrasses. 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.
