Image
In addition to beautifying North Carolina's highways, the bright poppies planted by NCDOT's Roadside Environmental Unit keep drivers alert.
Image
North Carolina highway basics

Today, 3000 acres of annuals, perennials, biennials, and native flowers bloom on North Carolina's roadsides, including daylilies, pink muhly grass, corn poppies, dame's rocket, lanced-leaved coreopsis, purple coneflower, narrow-leaved sunflower, and bidens.

When NCDOT finds a flower it wants to add to the beds, the North Carolina Department of Agriculture and Consumer Science investigates whether the species is appropriate for North Carolina roadsides. NCDOT must ensure that plantings will not interfere with croplands bordering the rights of way.

Since its inception, NCDOT's wild-flower program has received hundreds of letters and e-mails praising the beautiful landscaping.

OUTSOURCING PLANT PRODUCTION

Daylilies are another component of NCDOT's roadside beautification efforts. They typically flower during the drier months when wildflowers are not blooming.

“Initially, we wanted to plant about two acres of daylilies, but to do that, we needed 14,000 1-gallon daylilies,” says Smith. “None of the nurseries we asked had that many containerized daylilies, so we had to find another way to establish these areas.”

NCDOT purchased bare-root, single-fan daylilies from North Carolina nurseries and enlisted the help of the Caledonia Correctional Institution—a state prison in Northeast Carolina—to help the plants grow to a mature 1-gallon size.

More than 100 inmates are involved in harvesting the bare-root plants in the spring, pot them in gallon containers, and providing them to NCDOT for planting nine months later. The prison produces 200,000 to 300,000 daylilies a year. More than 2 million daylilies have been planted since the program began in 1997.

While highway aesthetics are important to NCDOT, its first priority is safety. In 1998, as part of North Carolina's Highway Safety Program, NCDOT implemented an $80 million cable rail installation along freeways to prevent motorists from crossing median lines into oncoming traffic. NCDOT must maintain the vegetation along the rails to maximize their performance during a collision.

Because it is difficult to get a mower underneath or immediately next to the cable rails, NCDOT developed a herbicide program to control the weeds in these areas. Crews apply pre-emergence herbicides containing pendimethalin in early spring or early fall, depending upon the weed species.

As the Roadside Environmental Unit demonstrates, vegetation managers need to focus on driver safety, managing budgets, beautification, and being environmental stewards. Smith describes vegetation management as a combination of art and ever-changing science. “We never know exactly what we'll have to respond to,” he says. “We just try to be ready when it comes.”

— Horton is a vegetation management expert for BASF in Anderson, S.C.