Sally Myers' rain garden is barely noticeable from the street, but it has a definite impact on the neighborhood. The garden does what rain gardens are intended to do: It collects and filters water that runs off of Myers' roof and yard. Without the garden, the excess water would run down the street and into the storm drain, where it then goes directly to the river.
Stormwater runoff also carries salt, sand, oil, fertilizer, plant debris and other pollutants into the river.
Myers is thinking about more than the pollutants the rainwater picks up on its way down the street, though.
"I keep thinking about how much money the city spends to maintain and expand the stormwater system," Myers says, but she understands the importance of it. Stormwater drainage is essential to decrease the risk of flooding where pavement and buildings prevent water from soaking into the soil. "The more water that we can keep out of the storm drains, the better."
Mosquitoes are not a problem, either. Myers' garden drains in less than 72 hours after a rainfall. Mosquito eggs take 10 days or more in standing water to develop into adults. Rain gardens should always be designed to drain within two to three days after a rain event.
Myers built her rain garden in a natural low area in the yard. She was lucky enough to have a neighbor with equipment who helped her make the area deeper. Rain gardens can also be created by digging the area out by hand.
All plants in a rain garden should be able to tolerate both wet and dry conditions. For the bottom, or lowest areas of the garden, look for perennials and shrubs that can tolerate a few days of standing water.
Myers uses a combination of native plants and plant species that are well-adapted to northeast Kansas growing conditions.
"Use deep-rooted plants that can soak up lots of water," Myers recommends.
In the bottom of Myers' garden, a filipendula is the first to catch my eye with its coarse, star-shaped leaves. Yellow flag (a type of iris) and daisies grow nearby, along with a variegated red-twig dogwood. Obedient plant (which might be more appropriately named disobedient plant) fills in bare areas in the bottom and on the sides of the garden.
Columbines, Golden Alexander (a native perennial with yellow flowers), Joe Pye weed (another native perennial), penstemon, asters, purple poppy mallow, native yellow coneflowers, amsonia, butterfly milkweed and other milkweeds line the banks of Myers' rain garden. A burning bush and a medium-sized viburnum grow nearby, and wild strawberries creep amongst a rock path that Myers uses to cross the garden.
"I tried to select plants that were good for butterflies and butterfly larvae, too," Myers says. "That might explain some of my selections, but they are all good for rain gardens, too."
Myers included an overflow area at the end of the garden that would allow excess water to spill over. So far, she says she hasn't seen enough rain to make the overflow necessary.
Rain gardens should be at least 10 feet away from homes to allow for adequate drainage from the foundation. Gardens should also drain away from homes and other buildings.
- Jennifer Smith is the Horticulture Extension Agent for K-State Research and Extension in Douglas County. Contact her or an Extension Master Gardener with your gardening questions at 843-7058.