Cover Story
Warm-Season Putting Greens in Richmond? A Review of NTEP Trial Results from CCV By Erik H. Ervin, Ph.D., Virginia Tech, with Troy Fink, CGCS, Country Club of Virginia
For
much of my research career, a major focus has been on understanding the stress physiology of creeping bentgrass and the cultural-management practices that can lessen putting green summer decline in the transition zone. Simultaneously, breeders were making major advances in warm-season turfgrasses for putting greens. Specifically, in the 1990s, ultradwarf bermudagrass cultivars were released that maintained excellent summer quality when mowed at ultra-low heights (0.090" to 0.125"). Champion, TifEagle and MiniVerde were some of the top early performers and have since dominated the warm-season putting green market. Selection was primarily based on density and leaf texture required for low-mow tolerance, with little regard for cold hardiness, shade or salt tolerance. Advances in Zoysia matrella, and in seashore paspalum breeding and selection, offer putting green cultivars with improved cold hardiness and shade tolerance (zoysiagrass) or salt and shade tolerance (paspalum). While cultivars of all three species (ultradwarf bermudagrass, zoysiagrass
and seashore paspalum) offer reducedmaintenance, summer-tolerant alternatives to creeping bentgrass, none come without challenges as we attempt their utilization in the mid-transition zone (35˚N to 39˚N). At these latitudes, winter survival will require covering the greens when temperatures drop below 25˚F for consecutive days.
Our research
In May and June 2013, McDonald and Sons Golf Course Builders (Andrew Green) worked with Country Club of Virginia (CCV) personnel and other sponsors to design and install a USGA putting green rootzone (90% sand/ 10% peat) near the Tuckahoe Creek Golf Course maintenance facility. On June 27–28, 15 ultradwarf bermudagrass, 11 matrella zoysia and 2 seashore paspalum entries were planted from plugs/sprigs provided by each breeder/ sponsor (see Photo 1 and Table 1). The CCV (Richmond, VA) site is one of 12 test locations, and at 37.5˚N, it is the second-farthest-north location. Given the need to mail 3 vegetative trays of 28 entries (84 trays per site) to 12 sites, sprigging/plugging rates
16 | Virginia Turfgrass Journal March/April 2015 www.vaturf.org
were significantly lower than industry standards. At our site, this approximately doubled the time required to reach 100% cover: 4 months for bermudagrass and paspalum entries, and 12 months for zoysia (see Table 1). Another factor that slowed our ability to lower mowing heights and establish plots to what could be termed “ready to open” was the need to edge plots and prevent entries from spreading into each other. Thus, some longer-term areas of open sand prevented our ability to rapidly lower the mowing height to one typical of “in-play” greens. By the end of 2013, the height was at 0.160" and was still there by the end of 2014. Before we review more data, let’s review 2013 and 2014 maintenance inputs and practices. In 2013, grow-in nitrogen consisted of 1 lb. N/1,000 ft2 every 2 weeks, for a total of 6 lbs. N/ 1,000 ft2 in 2013. Phosphorus and potassium were applied at less than 2 lbs./1,000 ft2. Topdressing consisted of applying 200 lbs. sand/1,000 ft2 every 3 weeks. One small disease issue (possibly Pythium blight) was seen on the seashore paspalums in late August, so Daconil and Subdue were