Incorporating a Rain Garden Into Your Landscape

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image of a birdbath filled with flowers and sitting in the middle of a flower garden

Rain gardens are wonderful ways for homeowners to recycle run-off from home drainage and in turn have an area of beautiful plants watered from captured water. A rain garden is not only beneficial to your landscape, but also in slowing water movement thus reducing sediment movement into lakes, streams, ponds, and storm water pipes. If you think a rain garden is something you would like to incorporate into your landscape, there are some things to first consider.

Site selection is essential in having a successful rain garden. The best location is an area receiving partial to full sunlight however, you must also keep in mind any underground structures such as utility lines already in place. Gardens should not be within 10 feet of the house foundation, should be at least 25 feet from septic system drain field, and should not be placed within 25 feet of a well head. In addition, rain gardens should be constructed where the water table is at least 2 feet below the surface of the soil. If you hit the water table when constructing your rain garden, consider turning it into a wetland garden instead.

Rain gardens are most successful in areas with well-drained or sandy soils however, they can be successfully installed on sites with clay soils. Digging a hole and taking a sample of the soil is the best way to determine the type of soil you have. Since soils in North Carolina are variable, even in the same yard, it is extremely important to note your soil type. A good indication of impermeable clay soils is by observations such as the site of interest has standing water or stays saturated for several days after a significant rain event, water poured into a dug hole still remains after two days, or the soil is gray or has areas of brown colors. If you notice these signs, your garden would survive best as a backyard wetland instead.

Rain garden size depends on the area you have and the site drainage area. The volume of water to be collected will be roughly equivalent to the amount of rain falling on impervious areas draining to the garden location. Using string or spray paint, outline your area to ensure the proper size and location. The garden should be dug 4-6 inches deep with a slight depression in the center. A berm located on the downhill sloping side of the garden should be covered with mulch or grass to prevent erosion. For well-drained soils, compost should be added to the top layer of the garden to allow plants to establish themselves better as well as aid in water retention.

Once your site has been prepared planting can begin. It is important to note that plants must be able to tolerate fluctuating levels of soil wetness. Native plants are a good choice since they are used to the environmental conditions and pests in the area. Planting several different species of native plants give depth and dimension to your garden as well as increasing the natural population of beneficial insects. For more information about horticulture contact Colby Griffin at 919-496-3344 or colby_griffin@ncsu.edu.