A garden on the roadside

June 11, 2001
In the average person’s life as a child passenger and later as a driver on the roads of the country, he or she may have no idea

In the average person’s life as a child passenger and later as a driver on the roads of th

In the average person’s life as a child passenger and later as a driver on the roads of the country, he or she may have no idea

In the average person’s life as a child passenger and later as a driver on the roads of the country, he or she may have no idea of the effort that goes into maintaining the roadsides.

Last October, the National Roadside Vegetation Management Association (NRVMA) met in Kansas City to discuss the inside story of how the grass gets mowed, the trees get trimmed and how the weeds are prevented from taking over the landscape. One of the highlights of the event was the presentation of the association’s annual awards for excellence in managing roadside vegetation.

The winners for 2000 were organizations that exemplified NRVMA’s commitment to the safety and beautification of the nation’s roadsides through responsible caretaking. The tools at the vegetation manager’s disposal include various herbicides, mowers, seed spreaders and erosion-control techniques.

ROADS & BRIDGES interviewed the winners who made the best use of these tools, including the city of Fairhope, Ala., which claimed top honors in the city category. Other winners were the Utah Department of Transportation (state), the county of Collin Texas (county) and Oklahoma State University (support).

Jennifer Fidler described Fairhope, Ala., as a paradise of tulips and other annual flowers blooming under spreading live oaks. The city puts up hanging baskets of flowering plants along the streets and even makes the trash cans look good by planting flowers on top of them. The homes of the 14,000 residents sit atop a hill overlooking Mobile Bay, with public parks and open spaces along the bayfront.

"Fairhope launched its beautification program in 1985 with a donation from the Rotary Club," said Fidler, who is the city’s public works director. Several years ago, a group of businessmen raised funds to plant 800 live oaks and crape myrtles along U.S. Highway 98, which runs through the city. "They are really tough trees," commented Fidler about the crape myrtles, which are native to the area. "They really hold up to adverse weather conditions. They’re very drought tolerant, insect, disease and pest resistant."

The live oaks are evergreen oak trees that are very popular in the area and grow well along coastal areas. Fairhope recently won an award from the Alabama Urban Forestry Commission for its tree program.

Once a week the city picks up litter and mows the rye grass it plants along U.S. 98. The city covers an area of about 10-12 sq miles, within which it is responsible for maintaining 94 miles of U.S. and county roads, plus the city streets, with a street maintenance budget of $1.8 million.

Along with the weekly mowing, Fairhope applies herbicide. "We only use Roundup, which we found is the safest chemical to use," said Fidler. The city sprays around the trees and along the roadsides in its area to keep the weeds down. "We’re also experimenting with growth retardants for our turfgrass management," she added.

Although the city averages 69 in. of rainfall every year, the summers are still hot and dry, so the city employs a watering truck that keeps the plants downtown from drying out.

The rainfall is partly responsible for Fairhope’s erosion problem. "We drain not only the city of Fairhope, but we’re in the watershed of our county," Fidler explained. Most sediment runoff comes from construction areas, where the earth gets disturbed, so the city passed an ordinance to try to control sediment runoff from development areas.

"We require our builders and developers to submit an erosion control plan during their development process so that they’ll show us how they’re going to control their erosion," Fidler said. "If we have silt and sediment that enters our roadway, we’ll send our street sweeper out and clean it up, but bill them for the hours that we used on the street."

Snakes you want in the grass?

"We have a lot of roads that go through miles and miles of open country that we used to try to mow to make it look aesthetically pleasing for the public," but not anymore, said Ira Bickford, roadside vegetation manager for the Utah DOT. Utah decided that it could stop mowing areas where there was no safety concern and save money, and at the same time provide habitat for wildlife. It is part of Utah’s Roadsides for Wildlife program, which is one part of the state’s six-year-old integrated roadside vegetation management (IRVM) philosophy.

"By reducing the mowing it lets nesting birds and different species that like that kind of habitat—rabbits and small animals and things—go ahead and take advantage of it," Bickford commented. "Some insects are specific to certain weed species that like roadsides, so as long as they’re not a noxious weed or a real problem then letting those plants stay there helps support a variety of wildlife."

The Utah DOT used to mow "right-of-way to right-of-way," which might extend from 15 to 100 ft from the pavement. Now, for areas outside of a city where there is no safety concern, the Utah DOT does what Bickford called "delineation mowing," in which the crews mow about 5 ft from the road—enough the see the roadside and the delineators.

The Utah DOT is in its third year of the Roadsides for Wildlife program, and the DOT works closely with the state’s Division of Wildlife. By not mowing, the state achieves another objective, which is to discourage big game animals, such as deer and elk, from hanging out at the roadside. Bickford explained: "By reduced mowing, you don’t have the green regrowth, and the deer and elk really like that green regrowth in the fall."

Utah used to spend over $1 million a year on mowing. Now, under the reduced mowing plan, the cost has dropped to about $800,000 a year.

The Utah DOT carved up the state into 79 stations, each with 100 miles of roadway. Each station supervisor becomes an expert in his or her area. Utah’s landscape goes from desert to 9,000-ft mountain passes. Part of the IRVM philosophy is to customize the roadside management to the climate in a particular station, rather than have a statewide mowing plan or a statewide spraying plan. And the plan has saved the state a lot of money, according to Bickford.

For example, the state used to spend over $500,000 a year on herbicides for the state’s 300,000 acres of right-of-way. When it instituted the IRVM and started spraying only the areas that really needed to be sprayed, that figure dropped to about $300,000 a year. The cost has risen since then because of inflation, but Bickford estimated that the state has saved close to $1 million over the past five years.

Noxious weed control is a major focus of the program. "Most of the noxious weeds are introduced from Europe, Asia and other foreign countries," said Bickford. The Utah DOT employs a strategy of spraying herbicides to clear out the weeds, then revegetating with native plants, mostly grasses but also sagebrush in some areas. "Our native species are not near as aggressive," Bickford continued, "so they tend to get overrun on disturbed areas and roadsides where these species come in."

The noxious weeds also tend to be broadleaf plants, whereas the native species are grasses, so Bickford can use broadleaf herbicides to good effect. Then it’s important to revegetate. Getting the native species re-established can take as little as 2-5 years in Utah’s mountainous areas, where there is 20-30 in. of precipitation each year, or as long as 3-7 years in the desert areas, which get only 5 in. of precipitation.

A healthy stand of native plants resists weed invasions. It also can act as a snow drift barrier, which is an advantage in a state like Utah that gets a lot of winter weather. On the other hand, in some places, the vegetation can actually make the snow pile up on the road. So, as part of the IRVM plan, each station supervisor has to decide which strategy works best in his area.

Another area where Utah has benefited—and saved money—with IRVM is in erosion control. The state used to do temporary fixes and then redo them a few years later. Now it follows a "hard armor" strategy using gabions, steel baskets filled with rock, to support the roadside and prevent erosion. They are more expensive at first, Bickford said, but in the long run they cost less.

Managed growth

Collin County, Texas, is already one of the largest counties in the state, and it is growing rapidly. Adding about 35,000 residents a year, the county, which lies just northeast of Dallas-Ft. Worth, is the third-fastest growing county in the U.S. It had a population of 500,000 in the latest census, twice as much as in the previous census.

For the county’s roads, fast growth means upgrading the surface from rock to hard pavement. The county has a master plan, though, called the Collin County Thoroughfare Plan, which gives a picture of what the county will look like 25 years in the future.

"If our traffic count on a road reaches 150 cars per day or more, then we put that on a list to be upgraded to an asphalt road," said Bobby Atteberry, director of public services and operations for Collin County. If the thoroughfare plan calls for the road to have 120 ft of right-of-way someday, rather than the 40 ft it currently has, then the county acquires the full amount.

"All of those roads are a typical county-type road," said Atteberry. "They have for the most part a 24-ft driving surface with ditches on either side. As we upgrade the roads to new roads, we acquire more right-of-way, and that’s been a big challenge for us with our vegetation."

Before, with steep and deep ditches, it was impossible to get a mower in to cut down the weeds that would grow up and block the view, so the county used herbicide. Now, with at least 60 ft of right-of-way on the new asphalt roads, the county has the option of using mowers in addition to or instead of herbicides.

"When we upgrade a road, we will redo all the drainage, install new culverts, reshape the road as needed, take out 90û curves, try to get some sight line of visibility improved on those roads," said Atteberry, "and then we build a new base and asphalt the road, put up signs and striping on the road. We also go back in and reseed and produce new vegetation so that we don’t have erosion problems out there."

Atteberry uses primarily Bermuda grass and fescue, a type of grass native to the area. The fescue will lie dormant and then root when the weather is right, so it can be planted in winter.

Atteberry uses a pre-emergent herbicide in late winter and early spring to check the weed growth. Then he does late spring and summer applications of a broadleaf herbicide to keep the weeds from encroaching on the road shoulders.

He also uses a dust-control agent extensively on the rock roads to keep the dust down during the hot, dry Texas summers.

Additionally, Atteberry uses brush cutters to keep trees and bushes back from the roadside. The county usually does not allow trees in the right-of-way, except for some old, established ones. In a few areas the trees grow over the road from both sides, creating a tunnel effect. The brush cutters can reach up and over to cut back the tree limbs.

Study in support of management

The roadside vegetation managers in Oklahoma can consult with their colleagues in academia for help with problems such as dealing with noxious weeds and calibrating equipment.

"We’re in the recommendation business," said Doug Montgomery, the extension associate in the Oklahoma State University (OSU) horticulture department. The OSU roadside vegetation project makes recommendations to the Oklahoma DOT, which sponsors the project, based primarily on site visits. Montgomery and his colleagues Lonnie Cargill, a program extension specialist, and Dr. Dennis Martin, an extension turfgrass specialist, travel to sites around the state to diagnose roadsides and make management prescriptions.

The OSU project also provides training to the Oklahoma DOT’s 600 certified applicators around the state.

"We provide initial training for new employees to teach them about herbicide use and also prepare them to take certification exams that are given by the Oklahoma State Department of Agriculture," said Montgomery. The university also runs about 14 annual continuing education workshops for the certified applicators. The workshops cover laws, regulations, chemicals, application techniques and equipment. "That’s where we give them any new information, any changes in the law, and we also usually each year try to give them a couple of new concepts," said Montgomery. "We try and challenge them in their training, as opposed to going over the same old stuff each year."

Much of the research at the OSU roadside vegetation project focuses on investigating the properties of herbicides and tailoring them to meet the specific conditions in Oklahoma. One of the big areas of research looks at controlling rye grass, which is becoming a problem in the state, according to Montgomery.

Another major research effort focuses on an annoying plant called sericea lespedeza. "Forty or fifty years ago, they were planting thousands and thousands of acres of highway slopes into sericea lespedeza and also private land, taking it out of ag production," recalled Montgomery. "They used that plant to build up soil, take it out of ag production, and the highway people were using it for slope stabilization.

"What’s happened to us is it’s become relatively invasive," he continued. "It chokes out all other vegetation, and it doesn’t have good characteristics for agriculture." Now that the plant has become a nuisance, some people in the state would like to get rid of it. Montgomery and his colleagues are trying to figure out which herbicides are active against the plant, how much of the herbicide is necessary and which application technique is the most effective.

The OSU roadside vegetation management project investigates a variety of other herbicides as well as those specific to sericea lespedeza. Montgomery and his colleagues are testing a combination of two broadleaf herbicides. It is a low-dose chemical headed for market by BASF. "We’re finding out now what rates we need to use and what plants it will be active on," said Montgomery. A lower use rate means less active ingredient in the environment and possibly less cost to the vegetation manager.

Another hot research topic is controlling johnsongrass: "Anybody in the southern one-half of the country, especially the southeastern third of the country, is going to have a very close relationship with johnsongrass," lamented Montgomery. "It’s one of the most common roadside weeds." Johnsongrass is an aggressive, warm-weather perennial grass that produces abundant seeds and rhizomes, which are underground stems that send out roots and shoots.

"It just grows too tall, too fast and requires mowing and creates sight distance problems," Montgomery said. On behalf of the Oklahoma DOT and roadside vegetation managers everywhere, Montgomery and colleagues would like to find a way to control this undesirable plant and other troublesome roadside weeds.

The trick is to know what to keep and what to discard. And they hope that today’s desirable plant does not become tomorrow’s weed.

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