Many gardeners consider a wet spot in the yard a headache because most plants can't survive in soggy soil. But Patricia Pennell thinks of a soggy area as a showplace waiting to happen.
Patricia, a Michigan environmentalist who specializes in watershed education, touts the benefits of rain gardens. In simple terms, rain gardens are basins where water runoff is collected. Thus, water is filtered into the earth instead of carrying pollutants such as lawn chemicals and heavy metals directly into storm sewers (which lead to rivers and lakes). The plants are bonuses.
Rain gardens are "a beautiful solution for water pollution," says Patricia, director of Rain Gardens of West Michigan, a nonprofit organization in Grand Rapids.
A rain garden can be any size, but to handle all the runoff from an average single-family home, it should be 150 to 400 square feet. "Any rain garden is better than no rain garden," Patricia says. "Every bit of runoff you can keep on your property makes that much more difference to our storm water."
Site it at least 10 feet from the house, preferably on a downward slope. Don't try to capture runoff on a hill above your house. "Water ends up in the most convenient place, so that place could be your basement," Patricia says.
Make your garden in a natural low spot or create a "dip' by digging. Shape the bottom like a saucer, leaving a large, flat area 6 inches lower than the garden's edges. If you have a storm sewer drain on your property, build the garden around it to benefit the plants.
There should be no standing water. Water collects in the basin during a rain, then goes into the ground.
Native plants adapted to handle excess water work best for rain gardens. Swamp milkweed (Asclepias incarnata) tops Patricia's list of favorites, along with queen of the prairie (Filipendula rubra), cup plant (Silphium perfoliatum), Culver's root (Veronicastrum virginicum) and turtlehead (Chelone lyonii).
Don't just dig a hole and plop in plants. Improve your soil first by deep-digging and adding compost. If you plant in poorly drained clay soil or if your soil is compacted (common from bulldozers in new neighborhoods), you'll create a water-holding, mosquito-breeding bog.
Don't place a rain garden under big trees where digging would disturb the trees' roots, and, finally, don't build your garden over the drain field of a septic system.
For information, or to get a list of Grand Rapids-area rain gardens you can visit, go to www.raingardens.org.