Effect of Colorant and Glyphosate Application Timing on Annual Bluegrass and Tall Fescue Control in Dormant 'Meyer' Zoysiagrass

Turfgrass managers commonly apply glyphosate on dormant zoysiagrass (Zoysia spp.) to control cool-season grassy weeds.  More recently, turfgrass managers are using paints and pigments to color dormant zoysiagrass throughout winter months.   Applications of glyphosate on dormant zoysigrass are well documented, but information concerning glyphosate and paint interactions is lacking.  In 2013 and 2014 experiments were conducted at Colbert Hills Golf Course (CH) and Stagg Hill Golf Course (SH) in Manhattan, KS to evaluate the effects of glyphosate and glyphosate + Endurant (Turfgrass Colorant) application timing for annual bluegrass (Poa annua L.) or tall fescue (Schedonorus arundinaceus Schreb.) control and zoysiagrass spring green-up. Research was performed on a ‘Meyer’ zoysiagrass (Z. japonica Steud.) fairway. Treatments were arranged in a 2 × 4 factorial, randomized complete block design with four replications.  Factors were two herbicide combinations and four application timings.  Herbicide applications included glyphosate (1.1 kg ha^-1) and glyphosate (1.1 kg ha^-1) + Endurant (16.6% v/v).  Application timings were mid -November, -December, -January and –February. Results indicate addition of Endurant to glyphosate applications did not influence zoysiagrass spring green-up or inhibit annual bluegrass or tall fescue control.