Chicago Tribune

Rain, rain, flow this way


If rain keeps falling in your yard and puddling with no where to go, you may want to consider putting in a rain garden.

"A rain garden manages stormwater runoff and improves water quality at the same time," says Laurie Fox, a horticulture associate with Virginia Tech's Hampton Roads Agricultural Research and Extension Center in Virginia Beach.

She gives a program on rain gardens and shoreline plantings at 1:30 p.m. Saturday during Spring Fling at Countryside Gardens on Mercury Boulevard in Hampton. The free daylong event also features programs on herbs and America's Anniversary Garden in red, white and blue themes that celebrate Jamestown's 400th anniversary.

Stormwater runoff can come from several sources - streets, driveways, roofs, gutters and adjacent properties. A rain garden, which is a natural or manmade depression, allows water to collect and slowly filter into the ground, replenishing the groundwater supply. The process also filters nitrogen, phosphorus and other contaminants that enter water through rooftops and driveways, according to the Alliance for the Chesapeake Bay.

Native and non-native plants that tolerate both wet and dry conditions are used to attractively landscape the rain garden. The area is also mulched with a material that floats as water collects, then settles back down again as the garden dries.

"There's a unique plant list for this use because it's not aquatic plants," says Fox. "A rain garden is designed to not stay wet long. It should hold water only two to four days, or it can become a mosquito problem."

In areas such as Northern Virginia, rain garden technology is replacing storm-water retention ponds, says Fox. Environmental research shows it's better to deal with runoff water on site rather than risk its force and volume causing erosion in waterways that eventually receive it.

When you create a rain garden - small or large - you get a functional site as well as an eye-catching one. Perennials suited for rain gardens include many garden favorites such as aster, beebalm, daylily, ginger, cardinal flower, black-eyed Susan, milkweed, hosta and calla lily. Many ferns, grasses and groundcovers also work. For shrubs, consider Virginia sweetspire, wax myrtle, oakleaf hydrangea, swamp azalea and bottlebush buckeye.

Virginia Cooperative Extension recommends a rain garden be at least 150 square feet or larger before using trees such as eastern redbud, downy serviceberry, Carolina silverbell and bald cypress.

Charts that calculate impervious surface to volume of runoff can help you determine what size rain garden you need, says Fox. She will provide helpful handouts during her program.

"A rain garden can be a beautiful addition to the residential landscape and provide gardeners an opportunity to try new plants," she says.

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