Water-Wise Turf for Texas

By Suzanne Labry, Contributing Writer

A nice-looking lawn and good sustainable practices need not be mutually exclusive goals.

Used wisely, turfgrass has a beneficial place in both the home and commercial environments. “Primary roles of turfgrass are soil stabilization, water conservation and filtration of air and waterborne pollutants," according to Aggie Turf. "Actively growing turf is highly effective in control of environmental pollution, such as the suppression of dust, glare and noise, and in heat dissipation, especially in the arid and semi-arid regions of the United States. Healthy growing turfgrasses act as biological filters and remove atmospheric pollutants. In addition to the positive benefits to the environment, turfgrasses play an important agronomic role in Texas."

As long as we shift away from large, manicured swaths of lawn and use turf strategically as a functional element rather than the whole focus in our landscapes, turfgrass can make a major contribution to the beauty, comfort and value of our homes.

And with the help of the turf-breeding wizards and urban water specialists at the Texas A&M AgriLife Research and Extension Center in Dallas, we can have our lawn and feel good about it too.

New techniques are being applied to come up with hybrids of turfgrasses for Texas that bring together multiple desirable traits, including the ability to withstand drought, lower water requirements, shade tolerance, resistance to pests and diseases, cold and heat tolerance, high turf density and color retention.

According to Dr. Ambika Chandra, associate professor of turfgrass breeding and molecular genetics, the first step in this process is to identify parental lines of cultivars from which to develop new hybrids.

For example, take St. Augustine (Stenotaphrum secundatum), traditionally one of the most popular grasses for Texas home lawns. The cold-tolerant cultivar ‘Raleigh’ is commonly recommended for the Lone Star State and a drought-tolerant ‘Floratam,’ another St. Augustine variety that is more sensitive to cold, is recommended for areas such as the Gulf Coast, where winter temperatures are warmer.

Using these two diverse lines as “parents” and applying innovative techniques that involve molecular biology, researchers are breeding a new hybrid that will include the best qualities of both.

Because ‘Raleigh’ and ‘Floratam’ have different numbers of chromosomes, they will naturally set viable seed at a very low frequency. Under laboratory conditions, however, researchers are able to perform what is known as “embryo rescue,” in which they cross the two varieties, harvest embryos from the cross after 21 days, and then grow the hybrid in artificial media.

It is a painstaking, expensive process, involving years of observation trials and field-testing. In fact, it took Dr. Chandra and her team at the Research Center nearly a decade and more than 8,000 tries before hitting on a cross that met their requirements.

In collaboration with the Turfgrass Producers of Texas, an industry trade group for sod producers that has funded the research since 2003, Dr. Chandra and her associates have developed ‘DALSA 0605,’ a St. Augustine cultivar that has impressed field-test observers with its ability to grow longer roots that are able to mine water from a deeper soil profile, thus making it comparable to ‘Floratam’ in its drought-tolerance.

What’s more, it has exhibited high tolerance to grey leaf-spot disease as well as the dreaded southern chinch bug, both of which can cause serious problems. As icing on the cake, so to speak, ‘DALSA 0605’ experienced excellent spring green-up following the extreme winters of 2013 and 2014. These extended periods of particularly cold weather caused ‘Floratam’ plots at the Research and Extension Center to die. Plots of ‘DALSA 0605’ not only survived but recovered as well as ‘Raleigh’ plots.

Through additional field-testing in other states (including Oklahoma, Georgia, North Carolina and Florida) as part of a collaborative project funded by U.S. Department of Agriculture, ‘DALSA 0605’ has proven to be adaptable to a wide range of habitats. In sum, ‘DALSA 0605’ has performed so well against all the benchmarks that it is about to have its commercial debut.

The Turfgrass Producers of Texas are expanding their production volume of the new hybrid and they expect to release ‘DALSA 0605’ to the public in late 2015 or early 2016. “We’re excited about the release of ‘DALSA 0605,’” said Dr. Chandra. “We feel that it has the characteristics that are desired by homeowners as well as landscape professionals.”

St. Augustine isn’t the only grass variety to receive attention from the breeders at the Texas A&M AgriLife Research and Extension Center in Dallas. For three decades they’ve been working on zoysiagrass, another type of turfgrass popular for Texas lawns. And zoysiagrass is particularly high on the list of Patrick Dickinson, urban water program coordinator at the Center.

“The zoysiagrass variety ‘Palisades’ has low water needs, it has good heat and cold tolerance, it has a low nitrogenfertilizer requirement, it grows incredibly thick to help choke out weeds, and — something that people really love — it is like walking on a soft carpet,” said Dickinson. “We tell visitors who come to the Center to take off their shoes and walk in it.”

Dr. Matt Elmore, assistant professor and extension turfgrass specialist at the Dallas Center, added, “The most important consideration when selecting zoysiagrass is to determine whether it is a Zoysia japonica, Zoysia matrella, or interspecific hybrid; these hybrids are often referred to as “matrella types” or manilagrass. Coarse-textured japonica types like ‘Palisades’ are more drought and cold tolerant than matrellas or interspecific hybrids like ‘Zorro.’ Although zoysiagrass is drought tolerant, it will display drought symptoms (wilt, leaf firing) before St. Augustine and Bermudagrass in good soils. This is a result of its drought-tolerance mechanism.”

When it comes to low water usage, buffalograss (Bouteloua dactyloides) is the hands-down champion, as long as you’re willing to embrace the characteristics that make it so.

Our only truly native turfgrass, buffalograss is able to withstand prolonged drought and extreme temperatures, and those characteristics, along with the ability to produce lots of seeds, enable it to survive the toughest environmental conditions. It also comes with a cool backstory:

Buffalograss provided food for the migratory herds of bison that once roamed the Great Plains and pioneers used it to make sod houses when no other material was available. Its relatively low growth-habit eliminates the need for mowing, assuming the homeowner is comfortable with allowing a six to twelve-inch lawn height and visible seedheads. It requires less fertilizer than other turfgrasses, and buffalograss is naturally resistant to pests and diseases. All these factors make buffalograss particularly suited for natural, xeriscape-type landscapes.

Buffalograss has some characteristics that make it less desirable for traditional lawn applications, however, including the fact that it does not do well in shade; its open canopy allows for more weed competition; its sensitivity to herbicides necessitates hand-weeding; it can’t handle a lot of foot traffic; and a lush green color is not its normal state.

A buffalograss hybrid, ‘Turffalo,’ was created in 2004 after 15 years of research by Texas Tech University and its partner, Frontier Hybrids. ‘Turffalo’ is said to address some of the problems with native buffalograss, including better tolerance of foot traffic, better color retention and the ability to handle some shade.

Over the years, researchers have made many improvements to Bermudagrass, one of the most commonly used and most waterwise turfgrasses in Texas, both for traditional lawns and commercial applications as well as pastureland. One of the best things about Bermudagrass — its ease of establishment — is also one of the worst.

It is so aggressive and its root and rhizome system so extensive that once it is established it is difficult to control, as anyone who has tried to remove it from a flowerbed can attest. That said, however, bermudagrass has been an important part of southern agriculture for at least 250 years. Because it has been around so long, it has been studied more than other turfgrasses.

Highly versatile, Bermudagrass can often survive without irrigation; it grows in a variety of soil types; it offers excellent resistance to heat and drought; it is salt-tolerant, which makes it ideal for coastal areas; and it will grow on hard surfaces and shallow soils, making it a good choice to prevent erosion. Although it will go dormant in cold temperatures, it readily recovers its green color when the weather warms up.

‘Tifway 419’ is the most common hybrid variety of Bermudagrass sold in the South and in addition to lawns, it is used on athletic fields and golf courses because of its ability to withstand heavy traffic and recover quickly from damage,” said Dr. Elmore. For the homeowner with kids and pets, it is an excellent water-wise choice. As a hybrid, ‘Tifway 419’ is grown from sod or sprigs rather than seed. Common Bermudagrass can be grown from sod, sprigs or seed, and the seed germinates and covers quickly. If you don’t count its bullying nature, about the only problem Bermudagrass has is the fact that it does not tolerate shade well.

All of the previously mentioned turfgrasses, with the exception of buffalograss, fall into the category of warm-season perennials. They originated in sub-tropical regions of the world and grow best when temperatures are between 75–90F. This means that they do most of their growing in the spring and summer in Texas, and will go dormant and turn brown over the winter.

To help those for whom the siren song of a year-round traditional lush green lawn is just too strong to resist, Dr. Chandra and her team are evaluating a hybrid bluegrass that crosses a native Texas bluegrass (Poa arachnifera), a cool-season perennial, with Kentucky bluegrass (Poa pratensis), the grass that most non-Texans think of when they think of a lawn.

“Of course it has a higher water requirement as compared to warm-season turfgrasses, but it definitely takes less water than Kentucky bluegrass and it will stay green in the winter under the right conditions,” said Dr. Chandra. “Our newest release, ‘DALBG 1201,’ is a dark green, dwarf-type hybrid bluegrass cultivar that requires infrequent mowing. It is a shade-tolerant cultivar that will withstand the heat of Texas and drought with a once-a-week watering restriction.”

In less water-conscious days, homeowners desiring a green lawn in all seasons would often overseed their existing lawn with perennial ryegrass, irrigating it all winter to maintain growth and color. Patrick Dickinson advises against that. “Some cities are even banning over-seeding because of the increased water requirement,” he said. “And if you think about it, a green lawn in winter really looks out of place in the Texas climate.”

Not over-seeding is just one of the cultural practices recommended by AgriLife experts. Here are some others:

• Select the right kind of grass for your home according to its intended use, planting location and maintenance requirements. Think about how turf areas will be used, and during which seasons.
• Reduce the size of water-sensitive lawns whenever possible and replace them with enlarged beds of appropriate plant material or hardscapes (decks, patios and walkways).
• Don’t put turf in areas that are long and narrow or small and odd-shaped because these are difficult to water efficiently.
• Turfgrass needs eight inches of soil to allow for a deep root system that can survive limited watering or extended drought. When planning turf areas, make sure to provide the grass with what it needs to succeed.
• Water your landscape early in the morning (before 10:00 a.m.). If you water in the heat of the day, most of your water will be lost to evaporation.
• Do not over-water your lawn. During the summer months, lawns typically require about one inch of water from natural rainfall or irrigation every seven days to stay lush and green. During winter, natural rainfall is enough to keep dormant turfgrass alive in most parts of the state unless it is exceptionally dry.

Remember, rain water counts. If it rains, you do not have to water your lawn. To better track rainfall, buy a rain gauge. Another option is to visit http://texaset.tamu. edu/. Here you can find a weather station near your location, and look at evapotranspiration (the amount of water transferred from the earth to the atmosphere) and rainfall. There is even an option to select “Turf/Landscape Irrigation.”

• Water your landscape by hand or run sprinklers in manual mode only after the appearance of drought stress.
• If you have an automatic sprinkler system, adjust the heads to water the landscape and not the pavement, and be sure to check your system regularly for leaks or misdirected spray heads.
• Install and maintain rain and freeze sensors.
• If possible, replace overhead sprayers with soaker hoses or drip tubes.
• Do not water on windy days.

Mowing your grass at a higher setting encourages deeper rooting. Do not bag your clippings; leave them on the ground, as they will return nutrients to the soil.

Use fertilizer with a high percentage of slow-release nitrogen, whether from synthetic or organic sources, and don’t over apply. Too much water-soluble nitrogen can increase water usage. Conduct a soil test to determine requirements for other nutrients, such as phosphorus, potassium, sulfur and calcium.

Our climate patterns may be getting more extreme and diminishing water resources may be the new normal in Texas, but we now have more and better options when it comes to turfgrasses that can withstand those challenges.

Thanks to the effort and dedication of turf breeders and researchers like those at the Texas A&M AgriLife Research and Extension Center in Dallas and their cohorts in the Urban Water Program who provide education on the best practices for maintaining our landscapes, we definitely can have our lawn and feel good about it too.