How to Make a Rain Garden

Pierce's Park Rain Gardens in Baltimore, Maryland featuring a dense garden of catmint, Japanese irs, and grasses.

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Rain gardens are growing in popularity throughout the gardening world, and why not? They’re eco-friendly landscaping features that also provide stunning havens for native plants, butterflies and birds.
A rain garden is simply a low-lying patch situated to collect storm water runoff from driveways, walks, roofs and other impermeable surfaces—run off that might otherwise end up in pristine wetlands, rivers and lakes. The strong roots of water-loving rain garden plants hold drenched soil in place, preventing erosion and filtering out pollutants before the runoff enters the groundwater. The same plants also form the core of what might become your favorite garden—a miniature wetland filled with color and wildlife!

Purpose of Rain Gardens

  • Soaks up rain and reduces runoff.
  • Resists erosion.
  • Filters pollutants of rainwater.
  • Replenishes groundwater reserves.
  • Creates habitat for butterflies, birds and other wildlife.
Here’s how you can construct your own rain garden in four easy steps:

Choose a Location

An urban rain garden.

Rain gardens need to be in the path of the runoff they are built to control, so place yours near sidewalks, streets, paths, gullies or roof downspouts. Locate your rain garden:
  • In sun or part shade.
  • On level ground.
  • At least 10 feet from buildings.

Test Your Soil’s Drainage

To test soil drainage dig a hole, fill with water and see how long it takes the water to soak into the ground.

Rain gardens must have porous, well-drained soil. Before you start planting, test your soil by making a small 12-inch (30 cm) deep hole and filling it with water. If it drains within 48 hours, you’ve found your site!

Lay Out Your Borders

Staking out an area of the landscape to create a rain garden.

Rain gardens come in all different shapes and sizes—from a long strip that runs next to a roadway to a kidney-shaped bed at the bottom of a sloped lawn. What’s more important than the shape of the bed is the size. A rain garden can process runoff from surfaces no greater than three times the size of the bed. This means for larger surfaces, like a roof, you may need to put more than one rain garden in, perhaps situating each one near a different downspout.

Pick Your Plants

Bringing home plants in a truck to create a rain garden.

There are two types of plants that work well in a rain garden – flood-tolerant plants that can sit in water for up to two days, the type that thrive in a swampy environment, and upland plants that would not survive a deluge but do well in wet areas around lakes, rivers and other standing water. Explore the native plants in your area that fit those criteria or check out our suggestions below.

Flood tolerant plants:

Flood tolerant plants: Broadleaf arrowhead, Zebra rush, Bog rosemary

Plants that thrive in wet conditions (though are not generally flood tolerant):

Plants for wet conditions: Black eyed Susan, Cardinal flower, Liatris, Milkweed, Joe Pye Weed
Rain gardens are one way to control the erosion that can damage lawns and foundation plantings. We’ve got even more suggestions on how to stop destructive soil erosion.
Rain garden


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