Come Together: Revegetation Projects Require Concerted Efforts

May 1, 2000

Planning is based on finding out everything possible about the site before a shovel, fork, backhoe, or excavator even touches the ground. Natural resource managers are discovering that with comprehensive site evaluations, the likelihood of a successful project is enhanced. As the population of the United States increases and more pressure is put on our lands, public and private shifts in the management of all our land is taking place. Resource managers are increasingly choosing solutions that are sustainable, solve the specific problems of the site, and are attractive to look at-all within the budget provided.

The components of a successful plan include several areas of assessment. First, a study of the unique issues of the site must be addressed: What’s wrong and what’s right with the site? What are the parameters of the project? For instance, roadsides must opt for low-growing plants, allowing for driver visibility and emergency access. What will the human usage be? Historical data collection is required, as it often lets the manager know why there is a problem in the first place and what solutions were tried previously. This can bring to light hidden bugaboos.

Soil evaluations are critical factors in the equation. There is more going on under the soil than on top of it. If the soil has been severely disturbed, graded, or completely removed-as in the case of mine sites-the project manager needs to know this. Watershed and hydrology assessment is important, as the greatest project can wash away in the first storm if these dynamics are not understood and planned for. Plant and animal inventories, sun and wind exposure, microclimates-these are all essential parts of a complete baseline study.

In assessing a site, ask for help; useful data might already have been compiled. The US Geological Survey has compiled topographic and geologic maps that are available to the general public. In California and in most other states, the local cooperative Extension Service can help with analyzing soil fertility, structure, and nutrient content. And don’t forget a maintenance plan. Often the forgotten step in the equation, a maintenance plan will address weed control (it’s what everyone sees when the installers have all left). Comprehensive collection of data will also help in getting the correct seed mix.

Paul Albright, president of Albright Seeds in Camarillo, CA, stresses the importance of choosing the proper seed mix-not only the species of seeds, but also the ratio of seed used with other types of seeds. This is because certain species will dominate and outcompete others if used in the same proportions. Sometimes nurse crops are used, such as Zorro annual fescue (Vulpia myuros ssp.), which is daylight-sensitive, and seed is set when the days get longer. This provides cover on the slope while waiting for other erosion control species to germinate and become established. Choose appropriate plant species for the site. Use an experienced contractor and reputable seed suppliers. Pay attention.

Each site is unique, and assessment of all the components will determine the most appropriate solution for the site in question. When creating a plan, remember Barry Commoner’s four universal laws of ecology:

  1. Everything is connected to everything else.
  2. Everything must go somewhere.
  3. Nature knows best.
  4. There is no such thing as a free lunch.

Roadsides of Yamhill County

Yamhill County is a farming community located in the lower Willamette Basin in northwest Oregon. It is characterized by the high precipitation from October through June that results in substantial runoff from roads and adjacent lands. Tim Stieber, district manager of the Yamhill Soil and Water Conservation District, points out, “Many roadside areas in Yamhill County do not perform all the needed roadside functions. Some areas are actively eroding or are devoid of vegetation, while others are overgrown with brush or noxious weeds.”

Roadside areas are unique compared to some other erosion control project sites. Roadside areas must perform multiple functions: (1) provide a legal and visual right of way, (2) drain road surfaces, (3) prevent land runoff from interfering with road travel, (4) protect the roadbed from erosion, and (5) prevent establishment of noxious weeds if the areas are properly vegetated.

Since all roadside ditches eventually drain into surface waters, roadside areas can provide another important function: filtration for roadway and adjacent land runoff. This runoff may contain heavy metals, salts, and hydrocarbons from roads and sediment and nutrients from adjacent lands. “Erosion of the roadside ditch area can also contribute sediment to the runoff stream if not properly stabilized,” notes Stieber.

The local maintenance policy in Yamhill County had been to chemically spray the shoulder of the road, continuing into the drainage ditch and up the other side-a distance ranging from 8 to 15 ft. This left the area free of vegetation and consequently available or weed infestation and usceptibility to erosion.

Sam and Nancy Sweeney, owners of Country Heritage Farms in Dayton, OR, thought there might be a better way to keep weeds such as pigweed, large crabgrass, and Canadian thistles out of their fields. Sam approached the state, and together they came up with a solution to weeds along the roads. The joint venture was initiated by Sam, and a committee was formed consisting of Yamhill Basin Council, Yamhill Soil and Water Conservation District, Polk and Yamhill Public Works, Oregon State University, and the Oregon Department of Transportation.

Using a zonal approach to seeding, two grass species were chosen: roughstalk bluegrass (Poa trivialis), which tolerates very wet conditions, and creeping red fescue (Festuca ruba) on the road shoulder, a low-growing grass. Creeping red fescue retains driver visibility, provides a thick thatch for erosion control and sediment entrapment, does not aggressively grow into adjacent fields, and is easy to maintain, requiring only one mowing per year.

The added benefit to weed control has been stabilized roadside ditches and improved water quality, as the vegetated ditches run clear. Stieber has been so pleased with the improved water quality and sediment control that he is encouraging other landowners to implement similar solutions.

Roadside revegetation is a cooperative project involving property owners, who provide the labor for seeding and maintain the ditches, and the Soil and Water Conservation District, which supplies the seed and the grading of the roadside. The latter has recently applied for a grant to buy a hydroseeding machine and to train district employees on how to use it. The district is expanding the program, starting with informational flyers and outreach programs, and it plans to vegetate the roads in the county in this manner.

After grading the contours of the adjacent drainage ditch along the road, Sweeney says the roadside is sprayed to completely remove any germinating weeds or grasses. “Next is a light harrowing by a four-wheeler or a small tractor. In our area the seed should be planted by September 15 and lightly harrowed in. The planting rate is heavy, similar to the rate on a newly seeded lawn. Fertilizer-nitrogen at about 40 pounds per acre-should also be applied. For both the seed and fertilizer operation I just use a shoulder-bag broadcaster; it costs about $20. It is surprising how quick it is to seed a roadside area.

“After that,” he continues, “in our area the fall rains usually start the seed germinating in several weeks. For very steep areas, our Soil and Water Conservation District has used a jute-mesh covering to hold the soil and seed in place.” The grass should be left about 6 in. high.

“Mowing shorter reduces the vigor and vitality of the grass,” Sweeney states. “One of the attributes of the creeping red fescue is that it grows to about 16 inches high, then falls over to about 6-8 inches.

“The vegetation of roadside areas was established for weed-control reasons, and it was a complete success. But what really surprised me were the benefits to water quality. About five years ago, one day after a thunderstorm in the spring, I observed two ditches. One was mine that was grassed, and across the road was a bare one without cover. The volume of water coming off of the bare ditch was approximately five times the amount coming out of the grassed one. This in itself was significant. But the real eye-opener was the quality of the runoff. The water coming out of the bare ditch was a very dirty brown and carried lots of sedimentation. But the water coming out of the grassed ditch was clear-the color of drinking water!

“As a result of these tests,” concludes Sweeney, “I was aware of the important function of roadside ditches in the movement of water to the riparian and natural waterways. Prior to that observation, I saw the ditches, but I didn’t really see the ditches. Now I see the roadside ditches as a critical link in the watershed. I learned that if they are properly constructed, vegetated, and maintained, they can play an important role in the improvement of water quality in a watershed.”

Wildflowers on an Old Mine Site

Located at 10,000 ft. in the Rocky Mountains, the Independence Mine attracts thousands of tourists each year. Cripple Creek and Victor Gold Mining (CC&V) operate the Cresson Project, a historic gold mine located between the towns of Cripple Creek, Victor, and Goldfield, CO. Two trails were built to accommodate the visitors, and the construction of the parking lots resulted in 1,700 ft.2 of steep slopes with high visibility and potential erosion problems. Topsoil was recovered from nearby areas and amended with approximately 7 lb./ac. of low-nitrogen fertilizer.

CC&V chose to use a custom wildflower mix from Applewood Seed Company in Arvada, CO. The custom mix includes 17 species of wildflowers, including Siberian wallflower (Cheiranthus allionii), black-eyed Susan (Rudbeckia hirta), and lupine (Lupinus perennis) and has been used successfully by CC&V on other projects. The seeds were lightly handraked into the seedbed.

Reclamation Coordinator Amy Meketi of CC&V reports, “In late April, the area received a 4-foot snow cover that helped settle the seeds into the soil and provided necessary early-spring moisture for germination. The snowfall was followed by several afternoon rain showers throughout the spring and early summer. With the cooler temperatures of the summer, the wildflowers did not reach full bloom until well into July. The area continued to receive rain throughout July with the heaviest storms of the summer, almost 2 inches in a 24-hour period, coming on the last days of July. The flowers proved to be not only beautiful, but also very effective in preventing erosion.”

Because of the high elevation of the site, the wildflowers are not expected to reseed themselves and will be seeded again this spring. This site was a success in preventing soil from washing down the hillside onto the parking lot and a hit with the tourists and local residents who appreciated the striking bouquet-filled hill.

Abandoned Mine Transformed

Michael Chaplinsky, president of Turffeed Inc. in Houston, TX, has taken his 14 years’ experience in fertigation on golf courses and applied it to an abandoned mine site in Ouray, CO. The old gold and silver mine is situated at 10,000 ft. and is being reclaimed for use as a mountaineering center.

“We’ll begin with a quick-starting annual rye cover to hold the soil and then die off at the end of the season, leaving the roots and the plants to become organics for the soil,” explains Chaplinsky. “The following season we will plant native grasses and plants [native to the mountain basin altitude of 10,000 feet].”

With only mine tailings to work with, he has successfully used fertigation on a test plot located on the outskirts of Ouray. “Fertigation is the injection of liquid nutrients and liquid bioproducts into the irrigation stream during irrigation. This practice constantly feeds the plants as it is watered to shorten the grow-in time significantly. This will promote rapid plant coverage to reduce erosion and damage to the planted areas. It has been used on golf courses, nurseries, and landscaped areas worldwide for many years.”

Chaplinsky is convinced that the combination of the right seed mix, careful irrigation, and proper soil nourishment techniques will resurrect this abandoned site and transform it into the main draw for visitors to the mountaineering center.

Carol Stream’s Shoreline

Four ponds, located in the residential community of Carol Stream, IL, were suffering from varying degrees of erosion. Douglas Willford, project manager with Landscape Resources in Montgomery, IL, says, “The initial goal was to provide a shoreline restoration and erosion protection method that was suitable for the conditions, economically feasible, low impact, and acceptable to the adjacent property owners. Wave action and wildly fluctuating water levels were a key problem with the ponds, and many conventional shoreline treatments were discussed as options, including riprap, gabion walls, gabion mattress revetments, and synthetic turf reinforcement.” Among the treatment options that included the use of native perennial seeding were a vegetated concrete armored toe (from A-Jacks made by Armortec, headquartered in Bowling Green, KY), emergent plant shelves, lunker structures, coir logs, and soil bioengineering. Each of these options incorporated a seeded native buffer that would extend up the shoreline to encompass the entire zone of water-level fluctuation.

“Turfgrass had failed to retard shoreline erosion, and the Village of Carol Stream was strongly in favor of utilizing native perennials and soil bioengineering,” recalls Willford. “The neighbors agreed to the less manicured look of native plants. The final proposed solution was a combination of coir logs, emergent plant shelves set in front of coir logs to dissipate wave energy, soil bioengineering, and a seeded native buffer zone.” The project began in the summer of 1999, an optimum time for construction as water levels were low and rains infrequent but not good for seeding.

Willford states, “The entire seeding area was to be protected by RoLanka’s moderately dense coir erosion control fabric that was laid out parallel to the shoreline and specified in an unusually wide format that would allow one roll to cover the entire seeded area, eliminating vulnerable seams.”

Two standard broad-spectrum native seed mixtures were selected from a local native nursery, one being for the emergent shelf and the other for the buffer strip. The emergent plant shelf species included bristly sedge (Carex comosa), fox sedge (Carex vulpinoidea), sunflower (Helianthus tuberosa), and swamp milkweed (Asclepias incarnata). For the shoreline buffer zone, 40 different species were planted, Indiangrass (Sorghastrum nutans) and black-eyed Susan (Rudbeckia hirta) being among the choices. Plant plugs were also utilized at the lower shoreline margins, which lessened the harm caused by persistent wave action.

The timing was complicated for this project, and as Willford points out, “We preferred that the seeds of native species stay dormant upon installation and be allowed to overwinter on the ground rather than germinate during the summer or fall and face either drought conditions or the inevitable hard freeze. If the native seeding did not establish immediately, the area would be vulnerable to an invasion of volunteer weed species.”

Because of the buoyant characteristics of coir fabric, staples are an inadequate anchorage in sloppy waters. The most effective way to adhere coir fabric to the soil is to establish a quick, solid stand of grasses through the fabric by planting a temporary crop of non-native annual grasses. Weather conditions were favorable, and the annual grasses exceeded 90% coverage. “The use of heavier coir erosion control fabric was certainly a factor in retaining what little moisture was available to the buffer seeding,” notes Willford.

The surface of the emergent shelf was set at just above normal water level for each pond, resulting in permanently saturated soils that were very conducive to the germination of the temporary grasses but not the emergent species that generally need long periods of cold stratification. The plant plugs benefited from the same wet conditions that aided the shelf seeding; all plantings exhibited vigorous growth rates and withstood the drought conditions. “The duration of the contract was two full growing seasons,” says Willford, “warranting close attention by the contractor to the seeding progress throughout the critical second season when the seeded native species begin to appear and are most vulnerable.”

So far, Willford is pleased with the results. “All indications show that the project will ultimately be very successful, further encouraged by many maintenance visits to the Carol Stream site.”

Hillside Saved

A burst irrigation pipe was the reason why Dwayne Werner, project manager for Wildlands Inc. in Richland, WA, was summoned to work on a job located on a steep hillside in East Wenatchee, WA. The 1.3:1 near-vertical slope consisted of highly erodible soils and harsh conditions. The surrounding vegetation is sagebrush and bunch grasses, and the decision was made to install a combination of native and non-native vegetation for the erosion control properties and for aesthetic purposes. Two options were considered for the use of an erosion control mat, and they went with a 3-D composite erosion control matting from Colbond, based in Arnhem, Netherlands. Werner states that this product was chosen because of the steepness of the slope and the highly erodible soil. This particular matting contains a nylon mesh bonded with a biodegradable mesh and will provide longer-lasting protection for the hillside. Werner says preparation of the area included filling-in gullies created by the leaking pipe and then leveling with a trackhoe. The seeding mixed used is one that Wildlands had previous success with on similar soils in the area and includes white yarrow (Achillea millefolium); Regreen, a sterile wheatgrass from Rainer Seeds of Davenport, WA; and Bloomer wildflower mix, offered by Turf-Seed of Hubbard, OR. The expectation was that the sterile wheatgrass would establish first, followed by the natives and wildflower mix. Once these species had established, a crew came back and installed bitterbrush (Purshia tridentata), sagebrush (Artemesia tridentata), and rabbit brush (Chrysothamnus nauseosus) propagated in 10-in. tubes and planted 10 in. on center. Werner strongly feels that the combination of using seed and larger plants is critical to the overall success of a site. After the area was planted, an application of Biosol from Rocky Mountain Bio-Products of Edwards, CO, was put down, and a sprinkler system was installed at the top of the hill. Werner insists on the importance of using many different best management practices in conjunction with one another. He concludes that the success of this project rests on the decision to use a wide variety of plant species-“both propagated shrubs and seed at a sufficient rate. Choose an erosion control matting that fits the application, and apply a fertilizer that acts as a soil builder in situations where you have very nutrient poor soils.”

Whether the private-property owner approaches the public agency or the other way around, it’s essential that the planning phase be conducted thoroughly. In all of the projects discussed above, the people involved assessed their project site, obtained site-specific data, and planned the project, taking into account the unique characteristics of the site. The expertise of experienced contractors and seed suppliers working in conjunction with locals, who were intimately concerned with the projects and very knowledgeable about what works and what doesn’t, led to a successful conclusion as well as heightened appreciation and participation by all. 
About the Author

Karen Brooker

Karen Brooker is a restoration horticulturist based in Santa Barbara, CA, and a frequent contributor to horticultural publications.