It is no secret that the West is in a drought. As water issues persist, the belt will continue to tighten on water restrictions imposed on golf courses. Removing irrigated turf and replacing it with low-water-use plantings is a proven strategy to reduce irrigation requirements on golf courses while preserving and arguably enhancing the golf experience. Deciding what to plant in turf removal areas can be tricky, but research supported by the USGA has helped to shed light on establishing native grasses and what species perform best in different environments.
A study conducted by Kai Umeda and Worku Burayu from the University of Arizona at two golf courses in central Arizona demonstrated that native grasses and Kurapia – a groundcover – can be successfully established and will provide acceptable cover and quality under minimal irrigation inputs. Ten different native grasses were planted as part of this study and several were identified as the best performers. Researchers found that, “when mowed twice during the year, the native grasses alkali sacaton (Sporobolus airoides), sand lovegrass (Eragrostis trichodes), purple threeawn (Aristida purpurea), and blue grama (Bouteloua gracilis) can be grown as year-round green grasses that have pleasant and attractive characters compared to being unmowed.” While overseeded bermudagrass requires about 6 feet of water annually, the native grasses have been successfully maintained with only about 12-15 inches of irrigation annually.
Fine fescue grasses (sheep, hard, creeping red and chewings) did not perform well in a study conducted in Fresno, California, but several native California grasses did show promise according to Maggie Reiter from the University of California Cooperative Extension at Fresno State. The top performers were spike bentgrass (Agrostis exarate), dune bentgrass (Agrostis pallens ‘Camp Pendleton’), California brome (Bromus carinatus) and purple needlegrass (Stipa pulchra).
Another study being conducted in the Fresno area is one of 11 national sites also evaluating warm-season grasses and native grasses. This study is supported by the USGA and NTEP and is led by NTEP executive director Kevin Morris. The native C4 grasses established faster and performed much better in the drier, western portion of the U.S. For example, the native grass blend ‘Habiturf’ – a three-way blend of buffalograss, curly mesquite and blue grama – and ‘Cody’ buffalograss demonstrated superior establishment in Dinuba, California, and St. George, Utah, but struggled in Citra, Florida.
In a more moderate climate like the San Francisco Bay area, grasses such as dune bentgrass (Agrostis pallens), six-weeks fescue (Vulpia octoflora), Idaho fescue (Festuca idahoensis), meadow barley (Hordeum brachyantherum), and purple needlegrass (Stipa pulchra) have been the top performers. Farther east in the Bay Area, where the weather is warmer, the C4 grasses such as blue grama, curly mesquite and purple threeawn are performing well.
Superintendents have learned some good tips for establishing native grasses and these are a few to consider:
- Don’t till the soil – this just brings weed seeds to the surface. Some have used a slit seeder to make shallow grooves or have used a spring-tine rake to lightly scarify the surface to help hold seed in place. Some have had good success with hydroseeding native grasses.
- Use a blend of native grasses – a monostand does not work well.
- Weed control is a big problem. Use preemergence herbicides for broadleaf weeds and plan on making postemergence herbicide applications for several years to favor the desirable species.
- Plant a temporary crop to compete with weeds. This may be a fine fescue crop that will allow the longer-term and more desirable native grasses to flourish.
- Be patient! It typically takes three to five years to achieve the desired look when establishing native grasses.
Readers can find summaries of the research on native grasses on the Turfgrass and Environmental Research Online (TERO) site.
West Region Agronomists:
Brian Whitlark, senior consulting agronomist – bwhitlark@usga.org
Cory Isom, agronomist – cisom@usga.org