The transition zone of turfgrass adaption, a loosely defined area in the central United States which includes Kansas, experiences wide ranges of temperature extremes and makes turfgrass management difficult. Water is a limited resource and its use for landscape irrigation is under increasing scrutiny. Warm-season turfgrasses are more heat and drought resistant than cool-season grasses, and their use results in water savings (Fry and Huang, 2004). In addition, warm-season turfgrass also require fewer pesticide and fertilizer inputs compared with cool-season turfgrasses (Fry and Huang, 2004). However, cool-season turfgrasses remain green late into the autumn and also green up earlier in the spring, whereas warm-season grasses turn brown after the first autumn frost and remain dormant until mid to late spring. Some turf managers in the transition zone may avoid the use of warm-season grasses because customers object to the brown color during dormancy.
The warm-season grasses buffalograss and zoysiagrass are well adapted to the transition zone because of their excellent cold tolerance (Beard, 1973). Among the characteristics of interest to buffalograss and zoysiagrass managers are extended fall color and early spring green-up (Fry and Huang, 2004). During winter dormancy, a dormant brown color gradually occurs after the first autumn frost, and once spring soil temperatures rise above 50 °F, color slowly returns (Beard, 1973). Buffalograss has a light tan to straw-brown color when dormant and an intermediate-to-fair spring green-up rate (Beard, 1973). In Kansas, buffalograss generally enters dormancy in early to mid-October and greens up in early May. As a result of its extended winter dormancy in northern climates, acceptance of buffalograss as a turfgrass species has been limited (Riordan, 1991). In Kansas, ‘Meyer’ zoysiagrass usually takes on a straw-brown color of dormancy in October and begins to green up in mid to late April (Okeyo et al., 2011). The dormancy period for buffalograss and zoysiagrass can be unappealing to turfgrass managers and golfers, especially when cool-season grasses that retain color longer in autumn and green up sooner in spring are grown in the same vicinity.
Measured visual color and quality of dormant buffalograss were improved in Nebraska after treatment with the turf colorant LESCO Green (John Deere Landscapes, Alpharetta, GA) (Shearman et al., 2005), but there is a lack of research with other products. In the southern United States, turf colorants have been used as an alternative to overseeding with cool-season grasses to improve color and quality of hybrid bermudagrasses (Cynodon dactylon × C. transvaalensis) and manilagrass (Zoysia matrella) during winter dormancy (Briscoe et al., 2010; Liu et al., 2007).
In Kansas, we found that the colorants Green Lawnger (BASF Corp., Florham Park, NJ) and Match Play Bermudagrass (Pioneer Athletics, Cleveland, OH) (referred to as Match Play Ultradwarf Super in Braun, 2014) applied at 262 gal/acre once or twice during dormancy of lawn-height ‘Chisholm’ zoysiagrass resulted in distinct differences and duration of acceptable color (Braun, 2014). Based on results by other researchers and our work with colorants on ‘Chisholm’, it is clear that more information is needed on how to most effectively manage colorants on buffalograss and zoysiagrass in the transition zone. Therefore, our objectives were to evaluate the effect of one vs. two colorant applications and application volume on persistence of green color in dormant buffalograss and zoysiagrass.
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