Garden Design

Five Tips to Designing a Rain Garden

Use these tips by Helen Kraus and Anne Spafford, authors of the award-winning book, Rain Gardening in the South: Ecologically Designed Gardens for Droughts, Deluges & Everything in Between, to plant your own rain garden this year.

1. Location, location, location! Be sure to site the rain garden where it will catch the most rain. Take time to study how water flows across your yard in a rain storm. The lowest point on your property is not ideal (unless the ground continues sloping down to your neighbor)—you want to capture the water before it gets to that spot. It is difficult to dig there and expect it to magically drain.

2. Keep in mind that a rain garden will flood for short periods after a rain storm. It also can tolerate long dry periods. The best plants for a rain garden are those that thrive in both moisture extremes.

3. A rain garden is exactly that—a garden. Whatever style resonates with you (naturalistic, informal, formal) it can be achieved in a rain garden just as it can in any garden. In addition to being beautiful and the envy of your neighbors, rain gardens also have the critical function of capturing and filtering storm water, one of the leading causes of water pollution.

4.  The filter bed is the factory of the rain garden. The key to creating the best filter bed is to amend your native soil with compost. Whether you have sandy soil or clay soil, compost is the ingredient that improves water retention (of sandy soil), water infiltration (of clay soil) and brings in microbes (those little critters that help break down many pollutants). Moreover, compost provides nutrients that help plants grow and thrive. If all you do is add sand and/or rock to your filter bed, you aren’t bringing in the bio component. Plants—especially our natives—will not grow well in that media. Additionally, clay plus sand does not improve drainage—that’s actually a good recipe for a brick!

5. A well-designed rain garden can have four seasons of interest—flowers, fruit, fall color, winter color. Just like any other garden, it can have additional functions (although not for vegetable-growing, which requires steady watering). So if you want to create a rain garden that attracts butterflies, you can!

Dr. Helen Kraus and Anne Spafford teach horticulture at North Carolina State University.  For more information on the book, visit www.enopublishers.org.