Native grass is ‘greener’ than turf

U. TEXAS-AUSTIN (US) — A lawn of regionally native grasses uses less resources to maintain than common turfgrass, making it better for the environment and also better for consumers’ wallets.

“We created a lawn that needs less mowing and keeps weeds out better than a common American lawn option,” says Mark Simmons, ecologist at the University of Texas-Austin.

Commercial and residential lawns cover about 40 million acres—more American landscape than any traditional agricultural crop. But keeping turfgrass looking good takes time, effort, and money and carries an environmental price tag as well.

U.S. lawn maintenance annually consumes about 800 million gallons of gasoline, $5.2 billion of fossil-fuel derived fertilizers, and $700 million in pesticides. Up to two thirds of the drinking water consumed in municipalities goes to watering lawns.

The findings, published in the journal Ecological Engineering.

“Most lawns use a single grass species, which requires inputs to maintain,” Simmons says. “The goal was to develop a more ecologically stable, natural alternative for lawns that are so important to many Europeans and Americans.”

The species that co-exists in natural grasslands can thrive without human intervention, so to test whether a mixture of grasses also provides a good lawn, Simmons and colleagues created multiple plots of grasses in an open field at the Lady Bird Johnson Wildflower Center.

Plots of non-native Bermuda grass were established from commercially available seeds alongside plots of Buffalo grass in various combinations with other native, short grass species. In 2009, researchers applied different mowing and other regimes to the two-year-old turf plots.

Traditional turfgrass and the native grasses responded the same to mowing once or twice a month, to two watering regimens and to the equivalent of foot traffic. However, the turf of seven native grasses produced a carpet that was 30 percent thicker in early spring than the Bermuda turf.

As temperatures climbed into mid-summer and all the lawns thinned, the mixed native turfgrass still stayed 20 percent thicker than Bermuda.

“If we had mowed more frequently, the Bermuda grass might have become denser because of the way it grows,” Simmons says, “but the point was to find something that took less work to maintain than Bermuda and other traditional turfgrasses.”

Although Buffalo grass also retained its lushness into summer, the mixed native turfgrass beat both single species (monoculture) turfgrasses in weed resistance. When dandelion seeds were added by hand, those plots grew half as many dandelions as the Buffalo grass or Bermuda grass plots.

How soon American lawns benefit from the findings depends partly on whether native grasses become more commercially available. The native grass combination that will likely work best will also vary with location.

“This is just the first step to showing that having multiple grass species, basically creating a stable ecosystem that is a lawn, may have advantages for some turfgrass applications,” Simmons says.

“But we need to apply the findings to different settings to move away from solely having lawns that rely on us for life support.”

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