HOW TO BUILD A RAIN GARDEN
You can contribute to keeping the area’s water clean by planting a rain garden in your yard. This environmentally friendly space catches stormwater runoff in its soil and filters out the pollutants so they don’t flow into wetlands, streams and waterways. Rain gardens can also lower your water bills and create a habitat for birds and butterflies.
CHOOSE A LOCATION
Find the area where the most runoff will drain into your rain garden. Roofs, driveways, patios and areas with compacted soils all produce runoff. Also, keep the garden at least 10 feet away from your house and other structures.
The size depends on how much stormwater runoff you hope to catch. These gardens usually range from 100-300 square feet. Dig a depression twice as long as it is wide, with sloping sides. Water absorbs fastest in sandy soil. Consider adding sand to your soil.
PREPARE THE GARDEN
Use plants with established roots, not seeds, because seeds will wash away. Apply heavy mulch or decorative rocks to protect the plants. If needed, give the plants an inch of water a week for the first year.
PLANT, COVER, MAINTAIN
Use wildflowers and native varieties because when they mature, they'll require minimal weeding. Here are some plant recommendations compiled by Washington State University. (Click on the plant for info.)
More plant recommendations: King County/Be RainWise Washington State University
“Autumn Brilliance” Serviceberry
(Amelanchier x grandiflora) Small deciduous tree with clusters of small white flowers in earlyspring followed by bright red fruit that attracts birds. Its light gray bark is attractive in winter.
(Hemerocallis spp.): Common perennial flower in Washington state that can grow 12 inches to 3-4 feet tall, depending on the cultivar.
“Blizzard” Mock Orange
(Philadelphus lewisii): Medium deciduous shrub with fragrant white flowers in spring.
(Cornus sericea): Broad-spreading shrub with deciduous medium green leaves. Clusters of small white flowers in spring give way to white or bluish berries. In winter, the stems turn bright red or yellow.
Tufted Hair Grass
(Deschampsia cespitosa): Ornamental grass that grows 2-3 feet tall and has numerous, attractive flower stems bearing minute flowers on airy open panicles.
(Mahonia aquifolium): Medium-large evergreen shrub with shiny dark green leaves. Showy and fragrant yellow flowers in spring give way to small, bluish-purple fruit.
(Physocarpus capitatus): Large spreading deciduous shrub that grows up to 13 feet tall. Deep green, shiny leaves and clusters of small white flowers in spring.
(Fragaria chiloensis): Ground cover with bright green leathery leaves and attractive white flowers.