With warm weather, Minnesotans’ thoughts turn to outdoor barbecues, lake cabins and, of course, mosquitoes. If you’re looking for a natural, environmentally friendly method of controlling mosquitoes at your home or cabin, consider installing a rain garden.
As part of street renovation in the Como Park neighborhood this spring and summer, the Capitol Region Watershed District is installing rain gardens.
Some residents have raised concerns that these gardens will increase the mosquito population, but in fact they will do the opposite.
Rain gardens are depressed or bowl-shaped landscaped areas that function as miniature wetlands. They’re designed to absorb storm runoff from a nearby impervious surface before it enters a body of water.
The Como-area gardens are strategically placed to absorb water before it enters Como Lake. At residential properties, a rain garden could catch water from a roof or driveway. Given that up to 70 percent of pollution in streams, rivers and lakes comes from storm runoff, any size rain garden will improve water quality.
A properly constructed rain garden will not provide habitat for mosquitoes. According to the Metropolitan Mosquito Control District, it can take from five days to a few weeks, depending on weather conditions, for a mosquito to develop from egg to adult. A rain garden typically infiltrates in less than 24 hours. In fact, bird baths and clogged gutters are more likely to increase the mosquito population than are rain gardens.
Rain gardens provide habitat for wildlife, and can increase the number and diversity of birds and butterflies in one’s yard. They also provide a home to dragonflies, which eat mosquitoes, so people who live near a rain garden may notice a decrease in the mosquito population at their next backyard party.
Rain gardens have economic benefits, as well. Homeowners will save money and time since a rain garden needs no mowing, fertilizing or watering. Also, by absorbing excess storm water, rain gardens reduce standing water and the likelihood of home flooding.
Aesthetically, a rain garden can be a beautiful addition to a home’s landscaping. According to Jeanna Smith of Earthworks Landscape Design, “Because rain gardens are specifically planted with plants that can withstand periods of extreme moisture and drought, these gardens will thrive regardless of conditions, with little homeowner maintenance.”
Smith recommends that a rain garden be at least 10 feet from a house to ensure that infiltrating water does not seep into the foundation. The best sites have full or partial sun. Native plants will fare best in the extreme conditions present in a rain garden.
Smith also suggests buying plants in gallon pots rather than starting from seed. This will increase a garden’s likelihood of success and minimize erosion. Some shrubs that can tolerate dry periods and temporary pooling of rainwater include serviceberry, willow, dogwood and honeysuckle. Perennials to try are flag iris, joe-pye weed, goldenrod and some ornamental grasses. For a more complete list, consult a local nursery.
Although one of a rain garden’s benefits is low maintenance, young plants will require extra care, Smith says. During the first year, it may be necessary to give the garden supplemental water during dry spells. Weeding is necessary until native plants are established. After that, the only maintenance required is periodic mulching, pruning and occasional plant replacement.