Washington State University: Lawns for a hot, dry future tested at WSU turfgrass research farm
Late summer has transformed Washington State University’s turfgrass research farm from waving meadows to dormant, golden stubble. But over in the corner, rows of a Pacific Northwest newcomer are tall and verdant despite summer’s heat.
Deep-rooted and heat-loving, Bermuda grass is one of about a dozen experimental varieties at WSU’s new Perennial Grass Breeding and Ecology Farm. Here, researchers test candidates for the lawns of the future: grasses that stay soft and green under hotter climates or minimal watering and fertilizer.
“One of our goals at the farm is to bring out new types of grasses that aren’t typically grown in our area,” said Michael Neff, farm director and professor in the Department of Crop and Soil Sciences. “We want grasses that work for our soil, for farms and lawns, and for harsher environments.”
Grasses for hot summers
Neff digs up contenders in wayside ditches and native prairie remnants, often spotting them from the highway. Varieties are also sent by the grass seed industry for testing. Seed production is the top priority: growers need good yields to profitably farm. Sustainability is also important: some of these hardworking grasses need to thrive on minimal or brackish water and endure climate extremes for life on reclaimed land, highway margins, or busy sports fields.
Neff breeds a turf-type bunchgrass called tall fescue for salt tolerance, allowing for watering with treated wastewater, and production of the rhizome: the multilayered mesh of roots that helps knit sod together. He also breeds native prairie junegrass and tufted hairgrass as part of low-water lawns or ornamental plantings; and fine fescues for low water use and heat tolerance through the National Turfgrass Evaluation Program.
“We’re watering them just enough to keep them going,” he said. “Some feel nice under your feet, even though the soil is bone dry.”
Bermuda grass seed is traditionally produced in the lower Colorado River Valley, where a 20-year drought threatens future production of a plant that can stay green with minimal water in summer. Climate in Washington’s irrigated Columbia basin makes it a potentially ideal place to grow this warm-season grass.
While the farm is a center for growing experimental varieties, its focus is Kentucky bluegrass. About 90% of U.S. Kentucky bluegrass seed, used in lawns throughout the world, is grown in eastern Washington, northern Oregon, and the Idaho panhandle. Neff’s team breeds bluegrass for higher yields, aiming for bountiful, reliable seed harvests. The shallow-rooted bluegrass grows well here, tolerating Washington’s dry summers by going dormant.
“Right now, it’s as brown as brown can be,” said Neff, who sees Bermuda grass as a potential blend pairing and is testing its Northwest performance. Thanks to the warm-season partner, ‘Bluemuda grass’ could maintain its green color in summer. “In the fall, they switch, with Bermuda dormant and the Kentucky bluegrass active and green. This lawn could stay green through spring, summer, and fall.”
For home lawns, Neff recommends less frequent, deeper watering, which can train lawns to be more drought-tolerant by encouraging deeper root growth.
Cooler parking lots and drought-beating roots
Living pavers made of grass could capture and treat pollutants before they enter groundwater. That’s the goal of Kate Kraszewski, stormwater ecologist in WSU’s School of Design and Construction, who is also looking at how homeowners can capture rain and stormwater to irrigate their lawns.
“Grass pavers could help offset the urban heat island effects created by traditional asphalt parking lots,” she said. On the farm, Kraszewski tests different grass blends to see which are the most resilient. Future experiments will examine how living pavement can handle vehicle traffic and capture road runoff.
“Parking lots require a lot of carbon, but they don’t sink any of it,” she said. “Grass pavers do.”
By putting organic matter back into the ground, and reducing erosion with soil-locking roots, perennial grasses help the soil, often with little to no human assistance.
“On a hike this summer, I found a stand of western wheatgrass that was beautifully green but getting hardly any water at all,” Neff said. “It’s got a coarse blade—not the super-fine turf you’d want to walk on in bare feet. But for a traffic circle, a roadside, or a green space in front of a business, it has a lot of potential.”