By Cornell Cooperative Extension

Landscaping for water quality is an approach that places less emphasis on lawns and more emphasis on woody plants.  It means maintaining the vegetation that already exists on your property and adding more shrubs and trees, particularly along streambanks and shorelines.

Why do this?  How do shrubs and trees promote water quality?

Woody plants can alleviate soil erosion

Over time, the loss of soil along banks and shorelines due to the force of water can cause significant loss of your property.  Soil that enters nearby lakes and streams carries pollutants and causes turbidity which can degrade water quality for drinking, recreating and for use by wildlife.   Planting and maintaining existing shrubs and trees can alleviate the natural erosive force of water. 
Plant roots strengthen banks and shorelines by holding the soil in place and absorbing some of the excess moisture.  The deeper roots of woody plants are more effective at stabilizing banks and shorelines because the deep roots prevent slipping of the soil layers and undercutting of the bank at the water’s edge.   While better than bare ground, the roots of lawn grasses and other groundcovers are too shallow to effectively restrict soil loss along banks and shorelines.

Bands of vegetation filter pollutants

Strips or bands of vegetation slow down the rush of water running down slopes and paved surfaces after storms.  More water infiltrates the soil allowing the plants and soil to filter out contaminants (including pesticides, fertilizer, soil, pet waste, salt and grease). This is important even if water from your property does not flow directly into a lake or stream.  Contrary to popular belief, storm sewers do not carry storm water to wastewater treatment plants.  Water that flows into storm drains or sewers ends up in the nearest water body.  You can improve water quality by increasing the filtering capacity of your property.  Once again the key is adding more woody vegetation to your property.  A mixture of shrubs, trees and herbaceous plants more effectively filters out pollutants than grass alone.

Are there any other benefits of landscaping with shrubs and trees?

Plants can reduce flooding downstream

When flooding occurs upstream, plants on the streambank intercept the floodwaters, slowing them down and reducing the extent of flooding downstream.

Plants are an important component of wildlife habitat

Habitat refers to the food, water, cover and nesting sites that all living creatures need to survive. Planting a diversity of native plants ensures that the needs of a variety of creatures will be met. Such plantings supplement the natural habitat.

Enhanced property values

Eroded shorelines and polluted water are seldom good for property values. Landscaping that enhances the beauty of your property while stabilizing the shoreline and contributing to water quality is a sound investment.

Satisfaction

Many people find that is satisfying to make changes that enhance the environment and protect our natural resources.