A rain garden is a saucer or bowl shaped place in the yard or garden where rainwater can be directed, and is landscaped with native plants. The purpose of a rain garden is to direct the flow of rain from a roof or driveway, thus reducing the amount of storm water that enters rivers, lakes and streams. A rain garden collects and absorbs the rain that would otherwise be wet areas or run off.

Rain gardens are typically landscaped with plants native to our area, which require less care, require less fertilization and chemical pesticides, are generally deep-rooted, and will provide food and habitat for butterflies and other wildlife. Rain gardens can be designed for full sun, partial sun, and full shade. They can also be designed for different soil types. By using different shapes to the garden, and by using different heights to the plants, rain gardens can be both functional and aesthetically pleasing. By adding plants that bloom early in the summer, during the summer, and late summer to early fall, a rain garden can be blooming almost constantly from May through September in northern Michigan.

more info: http://www.raingardens.org