Improving winter survival of interspecific hybrid bermudagrass in the Mid-Atlantic region through cultural practices

Winter injury can cause significant loss of hybrid bermudagrasses [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] in the transition zone. Current research has focused on high-value, low-acreage areas like putting greens, but those practices are impractical to implement on golf course fairways. To that end, multi-year research projects were conducted at three sites across Maryland and Virginia to investigate the influence of annual N fertility [2.0 lb N 1000 ft⁻² (early summer application) or 4.0 lb N 1000 ft⁻² (split applied early and late summer)] across multiple fall mowing heights (0.5 inches, 0.8 inches, or 1 inch) and to elucidate the effects of wetting agent (fall, fall + winter, or none) and irrigation (0.5 inches irrigation at <15% soil volumetric water content [VWC] or none) applications during dormancy on reducing winter injury of hybrid bermudagrass. Dry-down experiments were also conducted using plugs collected from field trials to impose an artificial freeze event and elucidate the effects of soil VWC on winter injury. Turfgrass quality and percent green cover were evaluated regularly as the turfgrass entered dormancy and throughout spring green-up each year. Late-season N applications helped retain fall green coverage without increasing winter injury and increasing fall mowing height did not impact winter injury. Temporary increase in soil VWC increased bermudagrass survival after a short-term freeze event and prevented root biomass loss. These studies demonstrate late-season N applications can help retain green color and increasing soil VWC prior to a short-term freezing event can greatly reduce winter injury.