Feature Article - November 2010
Find a printable version here

Landscape Solutions

Great Grounds Advice

By Dawn Klingensmith

Grass Roots Effort

Besides its green roof initiatives, Chicago for more than six years has avoided the use of chemicals in its parks. "Following natural lawn care basics, the park district keeps the grass 3 inches high, which allows the roots to grow strong and access water deep in the ground," said Zvezdana Kubat, assistant press secretary, Chicago Park District. "As a result, the taller grass naturally shades out some weeds. With the reduction in use of chemical weed killers, dandelion flowers grow back quickly, oftentimes overnight; therefore, we're spreading the word that the sight of dandelions indicates grass that is healthy and safe for patrons to play on."

The park district uses propane-powered, low-polluting lawnmowers and practices "grass-cycling," or leaving the clippings on the grass. "There's a significant amount of nitrogen in the grass clippings that acts like a natural fertilizer, helping provide nutrients to our turf grass in an environmentally friendly way," Kubat said.

Most turf grasses throughout the Chicago Park District are aerated rather than irrigated in order to help fight soil compaction, which is a common occurrence on lawns that are used as recreational surfaces. This helps water and nutrients reach the roots of the grass.

Bug Off

Santa Barbara County in California maintains 8,000 acres of parks and open spaces, and though different sites require different maintenance strategies, in all areas the county practices integrated pest management.

As a pilot effort for the past several years, Santa Barbara County has all but eliminated the use of herbicides and pesticides in one 680-acre region. This near-comprehensive proscription is occasionally reviewed on a case-by-case basis when a particular project requires very limited use of an herbicide—for example, to prevent reemergence of a non-native invasive plant in a native plant restoration project.

In this region, called South County, the ban has only been lifted once since 1997, to remove an invasive species that out-competes native plants for water.

A controlled flame with a burn bottle is used to kill weeds in parking lots, sidewalk cracks and decomposed granite areas, and black plastic covering is used to kill weeds in limited problem areas. The use of mulch in planter beds inhibits weed growth, while also discouraging snails and retaining moisture for plants.

Compost tea, made by steeping compost in water, is used throughout the county for fertilizing and soil enrichment. Eliminating regular use of broad spectrum herbicides does increase the amount of time and cost of weed abatement. In fact, the cost of mechanical weeding, including labor and equipment, costs the county up to 10 times more per square foot than for previous controlled use of herbicide.

"Sustainable landscaping on the whole can save money. North Lake College in Irving, Texas, in 2003 initiated a program to introduce native plants to the campus, with cost reduction as a primary objective (along with environmental stewardship, education and awareness, and aesthetic considerations). Since implementing the program, irrigation volumes have been reduced by 50 percent or more in converted gardens and landscapes. North Lake irrigates most of the campus with recycled storm water, and native gardens reduce usage in areas served by city metered water," said Grounds Supervisor Chris Marrs. Labor has been reduced by 70 percent, and seasonal plant material costs have been eliminated or reallocated.

Seattle University's grounds department maintains all outdoor areas on campus without the use of chemical pesticides, and has done so going all the way back to 1986. All landscapes are completely organic except for the athletic fields. The university does not see pesticide application as viable, even as a last resort. The grounds crew aims for weed suppression, not eradication, and also uses wood chip mulch, compost top-dressing, compost tea and beneficial insect release to achieve this objective.