Native plants are more adapted to regional environmental conditions than are exotic plants. They require less water, fertilizer and pesticides, which when used in excess can pollute groundwater and surface water bodies. Ground covers can help prevent weeds and reduce erosion, while plastic covers can act to increase runoff and erosion. Erosion causes increased amounts of sediment to wash into storm drains or directly into streams, where it can cover gravel spawning and rearing beds required by salmon and can reduce the amount of oxygen available to fish and other aquatic life. The root systems of trees and shrubs are more extensive and stable than those of grass and can help to prevent erosion.
Most ground covers require less water and maintenance than grass lawns.
Bark dust, when placed in areas where it can be easily washed away, can act to clog storm drains and cause flooding. Instead plant native trees, shrubs, woodland plants and wildflowers on streambanks. Larger, native plants can help control erosion, stabilize banks, provide habitat for wildlife, shade and cool waterways, and filter water that runs off the land before it reaches streams, improving water quality and instream habitat for fish and other aquatic life. Make chemical-free compost to provide fertilizer and mulch. Natural compost material can enhance soil productivity and serve as a protective groundcover.