During the spring of 1998 the North Carolina Department of Transportation (NCDOT) began a guardrail installation initiative which required over 1000 miles of newly installed median guardrail on North Carolina's major thoroughfares. The implementation of this program increased workloads and maintenance costs for the NCDOT. Turfgrasses currently used under and adjacent to guardrails include primarily 'Kentucky-31' tall fescue (Festuca arundinacea Schreb.) and bahiagrass (Paspalum notatum L.). Unfortunately, these species possess high maintenance requirements. Alternative species such as centipedegrass (Eremochloa ophiuriodes) or zoysiagrass (Zoysia japonica) would reduce maintenance costs on these thoroughfares due to lower maintenance requirements. Centipedegrass is a minimal input turf species requiring no more than 44 lb N/a/yr and infrequent mowing. It is adapted to a wide range of soil conditions, but grows best in sandy, acidic soils which make it ideal for increased use along roadsides. Further, these species improve motorist's visibility due to inconspicuous seedheads resulting in safer, more economical, and aesthetically pleasing roadsides. In a majority of these situations, centipedegrass was sodded into existing roadside vegetation which included turf species such as bahiagrass or tall fescue.
The purpose of this research was to determine management plans for these areas where centipedegrass or zoysiagrass was sodded into existing vegetation. Management plans included herbicide and plant growth regulator tolerance as well as practices to transition the roadside to centipedegrass or zoysiagrass in an effort to achieve a monoculture turfgrass stand. Experiments included centipedegrass tolerance to herbicides and plant growth regulators applied at seeding and soon thereafter, centipedegrass survival when subjected to various fertility regimes, zoysiagrass versus centipedegrass establishment from sod under roadside conditions, among others.
