New turf varieties will feature drought and salt tolerance

By Gary Raham
Correspondent

Back to Gardening Articles List

"Saltgrass can find water other grasses don't know exists," said Tony Koski, professor and Extension turf grass specialist at Colorado State University. This is not too surprising since it can develop a root system 9 feet deep.

"You can also irrigate saltgrass with salt water," Koski added. Saltgrass is, in fact, a halophytic species--a plant that "loves salt." Such a suite of characteristics make it attractive in a drought prone region like Colorado and during a time when more irrigation water for things like golf courses and large public use areas might derive from waste water sources with a high salt content. With a little bit of luck and help from some of Colorado's sod growers, Koski expects some saltgrass sod to be available this year or next.

The United States Golf Association is funding some of the basic research on saltgrass (Distichlis spicata) through the joint efforts of scientists at CSU and the University of Arizona. Saltgrass is an Arizona native that --if it can be made into a successful cultivated species (cultivar)--could go a long way in stretching fresh-water supplies sorely needed as drinking water.

Some of its assets--such as an aggressive root system--can make its use as a turf grass difficult. The grass must be grown on layers of plastic to keep the root system shallow enough to transplant, but so far the roots want to poke straight through and head for water. Currently, Koski and colleagues are putting in a lawn in a CSU dormitory complex from plugs--a technique that is used for planting Colorado's drought-tolerant buffalograss. Buffalograss roots can grow 5 or 6 feet deep in contrast to bluegrass that has a root depth of 10 to 18 inches.

Koski says Scotts will be promoting a hybrid bluegrass this year that is a mixture of Kentucky bluegrass and Texas bluegrass developed by Texas A&M University. Its heat tolerance and drought resistance also make it a good choice for some applications in Colorado.

On Koski's web site (http://csuturf.colostate.edu/) he emphasizes the need to make the intended use of the grass a prime concern. Will the turf get high or low maintenance? Does it have to look great or merely good? Will it get high use or moderate use? Is there a cheap water supply available for irrigation, and will that water be salty? There's a handy chart on the site that compares the relative virtues of tall fescue, buffalograss and Kentucky bluegrass for lawn use.

A nice lawn is more than merely ornamental. Grass--whether it's native grassland or human cultivars--sucks in carbon dioxide in prodigious quantities and helps ameliorate some of the global warming to which this gas contributes. Koski says a colleague of his, Dr. Yaling Qian, has been studying the ability of lawns to store carbon at a site in Nebraska.

"CSU is one of the first universities to look at this effect," he said.

Qian has been taking samples yearly for seven years, and Koski is hoping they will be able to find more government funding for this project. Unplowed or undisturbed turf makes a great "carbon sink," whereas plowed land releases CO2 into the atmosphere.

Koski has a grant pending for his saltgrass work as well. He needs to complete research that will help turf growers and their customers know how to properly take care of saltgrass--especially how to fertilize and water it in the most effective ways. They also need to be able to grow seed efficiently. "The seed production part may be a couple of years off," Koski said.

Saltgrass, like buffalograss and bluegrass, can also be an integral part of landscaping. Grass has a beneficial cooling effect around homes that is a result of water evaporating from grass blade surfaces as they busily turn carbon dioxide into sugars as they photosynthesize, basking in the Colorado sun. Here again, the function determines what kind of grass to select.

"Kentucky bluegrass is great for its cooling effects because it stays green longer," said Koski. "If it's brown it's not cooling."

For a grass that prefers its water briny and in moderation, however, saltgrass may be the perfect choice.