Released March 2, 2009
EAST LANSING, Mich. -- A rain garden is more than a collection of plants that tolerate wet soils -- it’s a living retention and filtering area for storm water that would otherwise simply run off.
Because storm water runoff can carry pollutants with it, establishing landscape areas to capture and clean rain water and snow melt can help protect surface and groundwater, says Bob Schutzki, landscape horticulturist at Michigan State University.
“Rain gardens will help contribute to a more sustainable environment,” Schutzki sums up. “And it can beautify home grounds as well as commercial and industrial properties. It’s a great example of the landscape serving aesthetic, engineering and environmental outcomes.”
Ideally, a rain garden is about one-third the size of the surface area providing the runoff. Existing soil drainage is an important consideration in sizing a rain garden. In its bare bones, it’s basically a shallow depression or basin surrounded by and filled with plants that can adapt to or tolerate changes in soil conditions. Rain gardens intercept runoff and allow it to percolate into the soil. When water arrives, the conditions are wet; when it leaves, the soils may be dry.
“Though the area is called ‘rain garden’, that doesn’t mean that it will necessarily be wet all or even most of the time,” Schutzki points out. “Rain gardens may remain dry for extended periods between rainfalls.”
Choosing plants for rain gardens involves matching the growing conditions with plants’ requirements, keeping in mind the changing soil conditions between rainfalls. Identifying plants for sun or shade is easy; identifying plants that tolerate both wet and dry conditions may require a bit more homework.
Though annuals can be added for instant seasonal color, the emphasis is usually on shrubs, small trees and hardy herbaceous perennials. For a woodsy look, start with trees and add a variety of ferns and other shade-loving perennials. Daylilies and iris are always a favorite in sunny locations. Cultivated varieties of native plants such as Joe-Pye weed, black-eyed Susans and coneflowers can create a wildflower meadow impression. Ornamental grasses offer a contrast in plant form and heights ranging from a few inches to several feet.
For assistance in determining whether a rain garden is appropriate for your property and designing and creating one, Schutzki recommends visiting the Internet, where you’ll find a host of Web sites with basic construction guidelines and plant suggestions. If obtaining information off the Web, remember to make sure the information is appropriate for your geographic area and soil type.
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http://anrcom.msu.edu/press/030109/030209_raingarden.htm
Contacts: Leslie Johnson, 517-432-1555, ext. 156
Bob Schutzki, 517-355-5191
