Enhancing Winter Aesthetics of Zoysiagrass in the Transition Zone with Colorants.

Zoysiagrass (Zoysia japonica) is a warm-season (C4) turfgrass that requires less water and fewer cultural inputs than cool-season (C3) grasses, but its widespread use by homeowners is limited because of its brown color during winter dormancy in the transition zone. Turf colorants are an option for improving zoysiagrass color during dormancy. Our objective was to evaluate colorants applied in autumn at three application volumes on persistence of color through the dormancy period.   Field studies were conducted in Manhattan and Haysville, KS from October 2013 to May 2014 on dormant ‘Chisholm’ zoysiagrass. The colorants Green Lawnger, Endurant, and Wintergreen Plus were applied in October in solutions with water at 748, 1497, or 2245 liters per hectare (L/ha) at a 1:6 dilution (colorant:water).  Intensity and duration of acceptable color (i.e., a rating > 6) of each colorant product increased with application volume.  In general, applications at 748 L/ha provided acceptable color for 8 to 14 WAT; 1497 L/ha provided acceptable color for 10 to 20 WAT; and 2245 L/ha provided acceptable color for 16 to 26 WAT. Compared to tall fescue (cool-season control), zoysiagrass treated with colorants had significantly higher color ratings between 8 and 24 WAT at 748 L/ha; 6 to 26 WAT at 1497 L/ha; and 4 to 26 WAT at 2245 L/ha.  Green Lawnger and Endurant applications resulted in a dark-green turf color, whereas Winter Green Plus resulted in a blue-green color.  Turfgrass colorants increased canopy temperature by up to 6.7ºC, but not soil temperature. Intensity and duration of acceptable color can be enhanced by increasing application volume of colorants.