This past year has been uncharacteristically dry. How dry is dry? By the end of September, more than half of the contiguous United States was in moderate to extreme drought conditions, according to the National Oceanic and Atmospheric Administration.
The lack of rainfall has not been lost on the turf industry.
Centipede lawns have low nitrogen fertility requirements and are popular with property owners in the Florida Panhandle and southern Alabama.
PHOTOS COURTESY OF SOD SOLUTIONS.
"Drought conditions and limited water supply continue to shine the light on the need for turfgrasses that have reduced irrigation requirements," says the University of Florida's Dr. J. Bryan Unruh, professor and associate center director at the West Florida Research and Education Center_ in Jay, Fla.
Dr. Milt Engelke, consulting agronomist & professor emeritus at Texas A&M University, agrees.
"Water is a critical issue. We're going to go to alternate water sources and less water" for irrigation, he says.
At research centers around the country, turfgrass scientists are focused on breeding new turfgrasses and identifying warm-season cultivars that can survive through a drought. One of the main warm-season turfgrass families being evaluated for its drought tolerance is zoysiagrass.
At the University of Georgia, Dr. Brian Schwartz started with 4,000 unique zoysiagrass accessions culled from the many thousands of zoysia progeny held at Bladerunner Farms in Poteet, Texas. From those, Schwartz identified some 40 accessions that he felt "weren't looking bad in the drought." He sent those grasses back to Poteet, and also to researchers at Purdue University, West Lafayette, Ind., to test the zoysiagrass cultivars under different soil and climate conditions. The word so far, according to Schwartz, is that the top three grasses at his research facility in Tifton, Ga., are also the top three at Purdue and in Poteet, also.
Efforts are also underway at the University of Florida, in conjunction with turf company Sod Solutions and the Florida Sod Growers Cooperative, to fund a new program called Turf Research Florida. The research initiative, says Justin Wallace, director of communications for the South Carolina-based Sod Solutions, "is a multiyear program to breed a more disease- and insect-resistant zoysiagrass, and possibly one that does not go off-color so quickly when drought sets in."
"Drought response among the warm-season grasses varies widely," Unruh says. "Researchers continue to elucidate drought response mechanisms. For example, some grasses gain their improved drought response through enhanced rooting (allowing water to be extracted from deeper soil depths) whereas others do it by altering their physiological responses (metabolism, transpiration and photosynthesis). Gaining a better understanding of these traits allows breeders to develop grasses that will persist under harsh conditions."
Still, it could take years to develop new turfgrass varieties.
Right now, there are a number of warm-season turfgrasses that have improved drought response used in residential and commercial lawns.
The beautiful home lawn in Naples, Fla., features Empire zoysiagrass, an increasingly popular choice for southern properties.
Industry experts seem to agree that zoysia leads the way as the go-to grass for low-water-use situations. Among the most widely known zoysiagrass varieties on the market today are: JaMur zoysia (medium textured) and Zeon zoysia (fine bladed) from Bladerunner Farms & The Turfgrass Group; Empire zoysia (medium textured) and Geo zoysia (fine bladed) from Sod Solutions; and UltimateFlora zoysia (medium textured) and PristineFlorazZoysia (fine bladed) from Environmental Turf.
Zoysias are becoming popular for home lawns in the South because of their appearance and wear and drought tolerance. Ongoing research aims to make them more resistant to diseases and insect damage, and to improve their color during drought conditions.
Still nice with fewer inputs
"The current trend in warm-season turf centers on sustainability with reduced needs for cultural inputs while providing a high level of visual and functional quality. Zoysiagrasses UltimateFlora and PristineFlora fit this trend as they are visually appealing yet require less fertilizer and tend to be more drought-tolerant than traditional St. Augustinegrass cultivars. They are also much less susceptible to certain insect pests, such as chinch bugs, reducing the need for insecticide. We think UltimateFlora and PristineFlora are key to providing sustainable lawns for homeowners and other turf venues in the southeast," says Dr. William Lee Berndt, president of Environmental Turf, Inc., based in Avon Park, Fla.
The main challenge with zoysiagrasses in the marketplace may be, as Unruh points out, that although zoysia is likely to survive a drought, its tendency to go off-color as a defense mechanism is something that homeowners may not understand.
"Though it is technically drought-tolerant, it does it different than other grasses. Zoysiagrasses go dormant and turn brown during prolonged drought. When homeowner Bob buys a 'drought-tolerant' grass, they will assume that it will stay green with limited water," Unruh says. The grasses' natural drought response may cause some homeowners to be "disappointed with zoysiagrass, because it goes off-color."
Therefore, if zoysia is to succeed as a drought-tolerant turf, further consumer education may be needed to explain the drought response.
David Doguet, president of Bladerunner Farms, has a new zoysia variety called Lowrider. One that, when released, could help address that issue. "It can go brown, but the minute water hits it, it comes back green," he says.
"Zoysias are really trending in the South right now because of their appearance, wear tolerance and especially their drought toughness," says Wallace.
There are other turfgrass families with some drought tolerance. Bahiagrass and buffalograss, says Wallace, may require less water for irrigation than, perhaps, a St. Augustinegrass, but "the problem is they both tend to have aesthetic shortcomings." And bermudagrasses, he says, have some drought tolerance "but require more mowing."
Other issues drive warm-season turf research. Shade tolerance, resistance to disease or insects, and low fertilizer requirements remain a part of the warm-season turfgrass matrix.
"Shade and low-light conditions continue to limit adaption of some warm-season turfgrasses. Although improvements in these grasses continue (e.g. Celebration and TifGrand bermudagrass), researchers at UF are attempting to better understand and to benchmark light requirements of the various warm-season grasses. Historically, a generalized number of hours of sunlight or percent of full sunlight for various grasses has been presented. These generalizations fail to provide definitive light requirements of warm-season turfgrasses. Researchers at UF have launched an aggressive research program to quantify the light requirements of warm-season turfgrass species and cultivars," Unruh says.
Even regional tastes and preferences are a factor in what grasses are successful in certain areas.
"In Atlanta, the customer wants a fine-bladed zoysia that works in a shady situation," says Aaron McWhorter, president of NG Turf, a sod production company, as well as of The Turfgrass Group, a turf licensing company. For his customers, McWhorter says Zeon zoysia is in high demand. To meet that demand, he grows 400 acres of the Zeon zoysiagrass on his Georgia farms.
Centipede grasses such as TifBlair Centipede from The Turfgrass Group, Santee Centipede and Covington Centipede from Sod Solutions, and Hammock Centipede from UF & Environmental Turf, have low nitrogen fertilization requirements. A medium-textured grass with a lime green color, the turf seems to be especially popular in the Florida Panhandle and Southern Alabama regions.
And, of course, St. Augustine and bahiagrass, two mainly commodity turfs, remain huge factors in residential home lawns and roadside applications, especially in Florida.
But, things are changing.
Market pressure, an informed buying public, advertising and marketing efforts on behalf of turfgrass companies, water restrictions, and, yes, drought, all influence the types of turfgrass installed and maintained in warm-season climates.
After more than 30 years of researching zoysia varieties, Engelke, for one, is convinced that zoysia is poised to become the next big warm-season turf. "Zoysia is a great tool to be able to work with. We will redefine environmentally friendly grass as zoysia," he says.
Stacie Zinn Roberts is president of What's Your Avocado?, a writing and marketing firm based in Mount Vernon, Wash. Reach her at firstname.lastname@example.org.