Tuesday, 23 February 2021 11:49

N.C. State turfgrass researchers collaborate with NCDOT for roadside grasses

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Zoysia research plots located along roadsides in North Carolina. Zoysia research plots located along roadsides in North Carolina. Dr. Grady Miller, NCSU

CHARLESTON, S.C. — North Carolina State University’s Turfgrass Program has been working on the selection, installation and evaluation of zoysiagrasses along roadsides throughout the state in collaboration with the N.C. Department of Transportation.


The project started with a pilot study back in 2015 when five NC State breeding lines were selected to be compared to four commercial lines on how fast they would be able to establish and outcompete weeds under low input conditions found on NC roadsides.

In January 2021, Drs. Grady Miller and Susana Milla-Lewis shared more information on this research during a North Carolina Sod Producers Association (NCSPA) online conference. Both are well-respected turfgrass experts at NCSU. Dr. Milla-Lewis is an Associate Professor in turfgrass breeding and genetics and Dr. Miller is a Professor and Extension Turfgrass Specialist. Dr. Miller is also the Co-Director for the Center for Turfgrass Environmental Research & Education at NCSU.

Following more extensive research on these lines being used on roadsides, Sod Solutions asked Dr. Miller and Dr. Milla-Lewis why the NCDOT is funding a project evaluating turfgrass.

Dr. Miller shared, “NCDOT manages vegetation in and around over 1,000 miles of median rail. Unlike some other states, NCDOT has grasses beneath their rails (some states use a concrete strip). Of course, there are also many areas of vegetation on roadsides other than just under guard rails that they also manage.”

Dr. Milla-Lewis said that the DOT is ultimately interested in safer roadsides with fewer inputs. “Grasses on road medians and shoulders provide a safer environment for motorists to exit the road, reduce dust which increases visibility, among other benefits” she added.

“Zoysiagrass is known to be a thick, sod-producing, and low-growing turfgrass that once adequately established has minimum weed invasion. With less weed encroachment than many other turfgrasses and generally slow-growing, it reduces maintenance in the long-term. Reduced maintenance can translate into increased safety due to a lower need for worker presence,” Dr. Miller said.

Dr. Milla-Lewis also added that reduced maintenance ultimately translates into budgetary savings. It is also helpful that zoysiagrasses are well adapted to North Carolina’s climate.

Future Applications

Aside from roadside venues, Drs. Miller and Milla-Lewis anticipate these zoysiagrass lines will also have residential and commercial potential. Although this research looked at utility use for zoysiagrass, they said any low-input area would have similar performance criteria. Dr. Milla-Lewis said that while these breeding lines are low-input, they still maintain good turf quality so she could definitely see them being used for landscape applications as well.

Dr. Miller shared that if the trials continue successfully, this may mean the public will see more consistent roadside turf consisting of zoysiagrass in the near future.