From Kansas City Gardener
Gardeners and landscape professionals across the metro area and beyond have made quite a splash with rain gardens and bioswales. Now that dirty work may yield some pay dirt.
At last count, over 300 residential rain gardens and a large number of commercial versions like bioswales and detention basins have been installed around Kansas City thanks largely to the 10,000 Rain Gardens initiative. The initiative draws attention to the impact individuals and organizations can have on our environment by catching rain where it falls in beautiful gardens filled with deep-rooted native grasses and flowers.
In April, 10,000 Rain Gardens will reprise its effective promotional campaign with a new twist. With two years under its belt, the initiative is seeking out area rain gardens to both identify interesting and beautiful examples and to insure all are registered at its website, www.rainkc.com. Area rain gardeners are also invited to submit images to local television stations. The best images will be shared with viewers during area weather reports. Of these, several gardens will be selected and their lucky gardeners will win a trip to Washington, D.C. The trip will include a visit with U.S. Representative Emanuel Cleaver II who serves on the House Select Committee on Energy Independence and Climate Change.
The deep-rooted plants and sunken profile of rain gardens help absorb stormwater runoff and reduce erosion. What you may not know is that rain gardens can be as beautiful as they are functional. In fact, many of our most beautiful regional natives need the type of regular moisture found in a rain garden to thrive. And, if you decide to add a rain garden to your landscape, it can be done as a weekend project.
To establish the size of your rain garden, calculate the square footage of the area where rain will fall and runoff. For example, let's take a 1000 square-foot roof panel with two downspouts. Divide 1000 square feet (the square footage) by two (the number of downspouts) and then by 3 to discover you should have a 167 square foot rain garden to treat the stormwater from the two downspouts channeled to the rain garden.
To calculate the number of plants planted on 18" centers, divide 167 (the square footage of this area) by 2.25 to find 74 plants. If your soil is extremely compacted or clayey, double your square footage figure and increase the size of your rain garden, OR amend your rain garden's soil (50-60% sand, 20-30% topsoil, 20-30% compost). If your area is very large, or you are revising an existing swale to make a bioswale, replace some or all plants with shrubs and trees that tolerate occasionally wet soil.
Most important, create a rain garden of some size. Even if your space is limited, you can benefit from a rain garden and help improve our area's management of stormwater. Any size will help, even a small rain garden.
Once the size is determined, site your garden at least 10 feet away from its foundation. Use a rope or garden hose to test different shapes for your garden's footprint. Within the footprint of the rain garden, create a slight depression by excavating six to 12 inches of soil. This also helps by removing existing vegetation. Mound this soil in a shallow berm on the down side of the garden. If your soil is extremely compacted or clayey, tilling a mixture of sand and peat into the soil will help improve the rain garden's absorption until the native plants mature.
Arrange your rain garden plants. There are a number of sample rain garden designs on the internet and in area publications, but it's simple to create your own. Just group your plants with height, color and seasonal bloom in mind.
During the first season, woodchip or gravel mulch will help prevent weeds during garden establishment. A quick weeding may be needed once a month and removing spent flowers will help prolong blooming. If your garden does not receive about one inch of water per week during the growing season, supplemental watering may be needed to keep plants blooming. Fertilization is not necessary.
To encourage new growth, do a late fall cleanup. Cut back plants to six inches tall and remove dead vegetation. After several seasons, you may divide large clumps and create additional gardens.
If you're not sure about how to select plants, or how to design, site and install your rain garden, don't worry. There are a number of local, qualified professionals who specialize in native landscape design, installation and maintenance. In fact, you'll find qualified landscape professionals listed on the www.rainkc.com website. These pros can provide anything from general site recommendations to a unique rain garden design and complete installation---or give you something in between. They will help you achieve your goals for a beautiful, low-maintenance, working rain garden, filled with songbirds and other watchable wildlife.
Think bold. Moisture-loving plants will grow taller and more robustly than their dry-site counterparts so allow for plants to grow up, fill out and have room.
Don't forget your greens. Native grasses, rushes and sedges provide textural contrast with large-leaved plants as well as year-round interest.
Plan for change. Get extra zip from any garden design by planning for a change of color scheme. A pastel spring palette of rain garden bloomers like Goat's Beard, Marsh Milkweed (Asclepias incarnata) and Blue Flag (Iris versicolor) will offer a whole new look when fall plants begin to bloom with a color scheme of violet, red and gold with New England Aster (Aster novae-angliae), Sweet Coneflower (Rudbeckia subtomentosa), Cardinal Flower (Lobelia cardinalis) and Showy Goldenrod (Solidago speciosa).
By Judy Allmon. Her company, Bluestem Landscapes, is a State of Missouri WBE (Women's Business Enterprise). She lives and gardens in Jefferson City and may be reached at 573-230-1196 or judy@bluestemlandscapes.com.
