Building a Rain Garden
Your rain garden should be located at least 10 feet from your home in a low
spot where water naturally collects. It should have at least one-half day of
sun and a gentle slope leading from your roof downspout, driveway or walkway to
the garden. You can create a low swale from the roof downspout to the rain
garden to ensure that water drains into the garden.
To build the rain garden, mark out a 150- to 450-sq.-ft. area, depending on
the size of your house and amount of paved areas. Remove the sod and dig a
shallow depression about 6 inches deep. Use the soil to form a berm on the
lowest side of the garden to retain water. A 6-inch-deep rain garden should
drain water within 7 hours. If the rain garden is deeper, the water may stay
longer, creating a mosquito-breeding site.
Rain Garden Plants
Select regionally adapted plants that can withstand periodic flooding and
offer seasonal color and interest. When fully planted, your rain garden
will look like any other flower garden in your yard. Plant in clumps of
at least three of each particular plant, and include ornamental grasses and
sedges for texture and to help prevent soil erosion. Create a special “rain
garden” soil mix of 50% to 60% sand, 20% to 30% topsoil, and 20% to 30%
compost. Dig this mixture into the soil to a depth of 2 feet before planting.
The native plants you grow will depend on where you live. Some examples are
swamp milkweed (Asclepias incarnata), queen of the prairie (Filipendula
rubra), marsh marigold (Caltha leptosepala), columbine (Aquilegia
maidenhair fern (Adiantum pedatum), Joe-Pye weed (Eupatorium
maculatum) and turtlehead (Chelone lyonii).
After planting, keep the plants moist, well weeded and mulched with shredded
hardwood bark. (Bark chips and nuggets will float away during heavy rains.)
Your rain garden will not only help reduce water pollution, but will also be an
inviting place for butterflies, bees and birds to visit.
Charlie Nardozzi, a nationally recognized garden writer,
book author, speaker, and radio and TV personality, has appeared on HGTV, PBS
and the Discovery Channel television networks. He is the senior horticulturist
and spokesperson for the National Gardening Association and chief gardening
officer for the Hilton Garden Inn. He prepared this article on behalf of the
National Gardening Association.
Pagoda Rose & White (Aquilegia
hybrida), hybrid columbine (native plant). Photo courtesy of Proven