Designed to collect runoff from roofs, driveways and other hard surfaces, rain gardens are 3-12 inch deep, saucer-shaped depressions filled with loose soil, rocks and native plants. Approximately 70 percent of pollution is caused by storm water runoff. Rain gardens help to reduce storm water pollution by capturing the runoff before it enters the drains. Once captured, the runoff then filters through the plants and soil, recharging the ground water and improving the overall quality of the watershed by removing pollutants, such as, oil, heavy metal, and aqua eco-system damaging nutrients. Rain gardens also provide an attractive option for resolving many types of drainage issues and often attract birds, butterflies and beneficial insects.
- Identify a low-lying area on your site that is able to catch runoff before it flows into storm drains or waterway
- Rain gardens should be located at least 15-20 feet from the home with a grassy buffer or a rocky area where the runoff passes through before entering the garden
- Consider positioning your garden so that any excess water will overflow away from your home
- Determine the size (generally, 150-400 square feet), shape, depth and budget for your garden
- Build a berm (low soil mound along the downhill side of the garden) and Dig the Garden!
- Don’t forget, soil amendments such as sand and compost will improve overall drainage
For comprehensive information and instructions related to rainscaping, please visit the Chesapeake Ecology Center. If you would like to visit a rain garden, a good example is Brookside Gardens located in Montgomery County, Maryland.
Incorporating Native Plants
Native plants thrive in local environmental conditions and are able to tolerate fluctuations in climate and water levels. By incorporating a variety of plants in your rain garden design you will create visual interest and aesthetic value. Try these native plants when designing your garden:
- Trees – Red Maple, River Birch, Sweet Bay Magnolia, American Holly
- Shrubs – Red Twig Dogwood, Pussy Willow, Clethra, Itea, Aronia, Grasses, Winterberry Holly, Bayberry
- Perennials – Hibiscus, Iris, Lobelia, Blackeyed Susans, Carex, Joy Pye Weed, Daylilly, Astilbe, Chelone, Creeping Jenny, Monarda