What is A Rain Garden?
A rain garden is essentially a carefully curated assemblage of flowering plants, grasses and bushes typically planted in a shallow basin. It's engineered to absorb surplus rainwater runoff that originates from impervious surfaces like roofs, driveways, sidewalks and patios.
Despite their name, rain gardens aren't always wet. Instead, they're dry most of the time, as opposed to a water garden that features a pond or some other body of standing water.
Rain gardens are both an attractive and cost-effective method to mitigate runoff from your land. What's more, they aid in filtering pollutants from the runoff and offer a habitat for various forms of wildlife, including pollinators and birds.
What Plants Are Best for A Rain Garden?
Plants for a rain garden should be able to tolerate both heavy watering and periods of drought. They should be native to the area, as they will be more tolerant of local conditions and provide habitat for local wildlife.
Here are some examples of plants that are often used in rain gardens:
Astilbes—They thrive in moist to wet soil conditions, which makes them ideal for rain gardens. Their fibrous root systems bind the soil together, reducing erosion to help stabilize the rain garden.
Elephant Ears—These giant, tropical perennials can tolerate periods of inundation and high moisture levels. Their massive, heart-shaped leaves provide excellent ground cover, helping to prevent erosion.
Ferns—In addition to their excellent water tolerance and ability to prevent soil erosion, ferns provide a lush, verdant look. Many varieties thrive in partial or full shade, ideal for gardens that don't get much direct sunlight.
Daylilies—With their tolerance to varying moisture levels, low-maintenance nature, aesthetic appeal and adaptability to different light conditions, daylilies tend to be excellent performers in rain gardens.
Siberian, Japanese and Louisiana Irises—All are known for their ability to thrive in areas with high moisture levels, but they can also handle temporary dry spells. These irises also offer beautiful, showy flowers.
Coneflowers (Echinacea)—Their blooms attract a range of pollinators, adding to the biodiversity of your rain garden. The plants are adaptable to a wide range of soil and weather conditions and require little maintenance.
Remember, the most appropriate plants for your rain garden will depend a great deal on your specific region and the conditions in your garden. They will do the best job of managing and reducing stormwater runoff, providing habitat for wildlife and enhancing the beauty of a landscape.
How Should You Add New Plants in A Rain Garden?
Here are some tips on how to add new plants to a rain garden:
Choose the right plants. Rain gardens are typically wet for a short period after a rainfall, and then they drain and can be dry for a long time. Therefore, you need plants that can handle both conditions. Native plants that are adapted to local weather and soil conditions are often a good choice.
Understand your garden's water flow. Not all parts of your rain garden will have the same amount of moisture. The center of the garden will typically be wetter than the edges, so plan your planting accordingly. Place plants that can handle more water in the center and those that prefer drier conditions on the edges.
Prepare the soil. Before planting, prepare the soil by removing weeds and other debris. If the soil is compacted, loosen it with a garden fork or tiller to improve drainage. You may also want to add compost or other organic matter to improve the soil's structure and fertility.
Plant properly. Dig a hole that is as deep as the root ball of the plant and twice as wide. Place the plant in the hole, making sure the top of the root ball is level with the soil surface. Backfill the hole with soil, pressing it gently around the plant. Leave a slight depression around the plant to help hold water.
Add mulch—but not too much. After planting, apply a layer of mulch around the rain garden plants. This will help conserve moisture, suppress weeds and regulate soil temperature. Be sure not to pile mulch against the plant stems, as it can cause rot.
Water wisely. After planting, water thoroughly to settle the soil. Then monitor the garden to see how it handles rain. If some plants are too wet, you may need to move them to a drier part of the garden. If some rain garden plants are too dry, they may need to be moved to a wetter area.
Care and management. Once established, rain garden plants should require minimal maintenance. However, you may need to water some of them during dry periods, especially while the plants are getting established. Weeding will also be necessary until the plants fill in and start to crowd out the weeds.
Throughout the process, keep in mind that the goal of a rain garden is to improve water quality, create wildlife habitat and add beauty to your landscape. Choose plants that will help you achieve these goals.