Age-Old Wisdom meets Modern Tools
What are the Best Plants for a Rain Garden?
Rain garden in the Allen Centennial Gardens on the campus of the University of Wisconsin-MadisonJames Steakley
With a rain garden, use—don’t lose—all the rain water that falls on your paved areas and roof. Learn more about rain gardens—plus, here are two rain garden designs featuring plants for both sun and shade.
These designs come from The Old Farmer’s Almanac Garden Guide. Get the latest edition here!
What is a Rain Garden?
A rain garden is a shallow, bowl-shape area that collects water runoff from impervious surfaces such as downspouts, sump pumps, paved areas, roofs, driveways, walkways, and lawns. Often, the heavy rain from a thunderstorm comes down so quickly that the water runs off rather than soaking into the ground.
Like a native forest, rain gardens use heavy rain to recharge the aquifer, support wildlife habitat, and also filter out toxic materials before they can pollute streams. Whether you deal with drought, the rising cost of municipal water, or simply want to make the best use of our water, Mother Nature is providing this precipitation for free.
Rain Garden Plants
Plants of all types and sizes help to manage storm water:
- Trees and large shrubs deflect rainfall, slowing it down before it reaches the ground and allowing it to soak into the ground and not run off immediately.
Tall grasses and other perennials act as filters, sucking up water, trapping pollutants, and preventing silt from being carried off into ponds or rivers.
Well-established, deeply rooted plants hold soil and direct water into the subsoil.
See our lists of rain garden plants for sun and shade for more planting ideas, below.
5 Benefits of a Rain Garden
What do you gain when you catch the rain? Shower power! An inch of rain on a 100-square-foot surface results in 60 gallons of water!
Here are just five of the many benefits:
- Reduced risk of water in the basement
- Recharged groundwater supplies (a rain garden soaks up at least 30% more water than a lawn)
- A wildlife habitat (birds, butterflies, and beneficial insects will be drawn to the garden)
- Lower water bills
- A cleaner environment
Consider the Pollution
Storm water runoff, from flooding or even heavy rainfall, contains 70 percent of the pollution that flows into our lakes, ponds, rivers, and streams. Polluting sources include …
- roads, parking lots, paved driveways, and sealed surfaces (including roofs) that contain oil and other contaminants
- pesticides and lawn treatments that contain high concentrations of nitrogen and phosphorus
- pet and other animal poop
Creating a Rain Garden
Creating a rain garden can be as simple as directing the flow of water from your roof to a spot that you’ve already planted with water-loving plants—or, you can start from scratch. The size of the garden depends on the size of the impermeable area draining into it. Aim to make the bed 20% to 30% the size of the roof or driveway from which the water is being funneled.
Create a basin by digging out dirt from a dry area at least 10 feet downhill from the water source. (Avoid directing runoff to a naturally low spot that is already saturated with water or to your septic system.)
Replace heavy soil with one-half sand, one-quarter compost, and one-quarter topsoil—a fast-draining mixture.
Pile stones and extra soil on the downhill side of the garden to act as a berm and create a bowl where water can pool to a depth of about 6 inches.
If water does not naturally flow to your rain garden, dig a shallow (3- to 4-inch-deep) trench from your downspout to the garden, line it with landscape fabric, and cover with stones to create a streambed effect.
Plant the center of the garden with perennials and native plants that tolerate wet feet. Around these, place plants that tolerate occasional standing water. At the outer edges, set plants that prefer drier soil. Mulch with compost or shredded hardwood (bark chips may float away in a heavy rain). If the water that flows into the garden washes out the mulch, break up the flow entering the basin with a well-placed rock or two.
Your rain garden functions like a living sponge of soil, plants, roots, and mulch. It should not become a breeding ground for mosquitoes: The water does not stand.
A rain garden not only is a beautiful addition to your landscape but also supports greater biodiversity and is environmentally sustainable.
Rain Garden Designs
Both of the below rain garden designs are meant for a 12 x 24-foot space but are adaptable to smaller areas.
Note: In below plant lists, some plants are linked to growing guides with pictures. Others can be easily found via Google.
Rain Garden for Sun
Plants set into a rain garden that gets full sun must be able to endure both occasional flooding and dry spells.
Sun Rain Garden Plant List
In the center, plant #1 to #6. For the drier, outer edge, plant #7 to #14.
- Summersweet (Clethra alnifolia ‘Ruby Spice’), a woody shrub that bears fragrant, pink, bottlebrush flowers in the summer. 5 to 6 feet tall; Zones 4 to 9. One plant.
- Red osier dogwood (Cornus sericea), which has white blossoms in spring and reddish-purple leaves in the fall—although its most attractive features are its red stems, which lend winter interest to the landscape. 6 to 10 feet tall; Zones 2 to 8. One plant.
- Blue flag iris (Iris versicolor), which brightens the rain garden with lavender-blue flowers in the spring. It looks very natural in a wet setting. Avoid the yellow flag iris (Iris pseudacorus), which is an invasive species that will take over. 2 to 4 feet tall; Zones 3 to 9. Four plants.
- Joe Pye weed (Eupatorium maculatum), which has purple flowers in late summer that butterflies can’t resist. 3 to 5 feet tall; Zones 3 to 7. Two plants.
- Astilbes (Astilbe), which are long-lived, moisture-loving perennials that will thrive in the sunny rain garden if planted where they get some afternoon shade from taller shrubs nearby. They bloom in summer and are available in pinks, reds, purple, and white. 1 to 3 feet tall; Zones 3 to 8. Three plants.
- Daylilies (Hemerocallis), which may not be natives but can keep your rain garden in bloom over a long season if you plant early, midseason, and late varieties. Assorted heights and a rainbow of colors are available. Zones 4 to 11. Five plants.
- Blueberries (Vaccinium), whether highbush (up to 5 feet tall) or lowbush (up to 2 feet tall) varieties, which add both a flowering shrub and an edible fruit to your landscape. Zones 3 to 8. Two plants.
- American cranberry (Vaccinium macrocarpon), which is a pretty, ground-covering shrub that also bears edible fruit. About 6 inches tall; Zones 2 to 7. Six plants.
- Bee balm (Monarda), which in summer features brilliant-red, pink, or white flowers that attract hummingbirds and butterflies. Look for a mildew-resistant variety. 3 feet tall and wide; Zones 3 to 9. Two plants.
- New England aster (Aster novae-angliae), which will carry the show into fall with its bright, violet-purple flowers. It gets quite tall but can be cut back to half its height in June to create a shorter and bushier plant, if desired. Up to 6 feet tall; Zones 4 to 8. Two plants.
- Sneezeweed (Helenium autumnale), which bears sunny yellow flowers in late summer. It is highly adaptable to wet or dry soil. 3 to 5 feet tall; Zones 4 to 8. One plant.
- Meadow anemone (Anemone canadensis), which is deer-resistant and salt-tolerant. This tough little perennial bears pure-white blossoms in late spring. 2 feet tall; Zones 2 to 9. Two plants.
- Blue cardinal flower (Lobelia siphilitica), which has spikes of true blue flowers in late summer. 2 to 4 feet tall; Zones 5 to 9. Six plants.
- Butterfly weed (Asclepias tuberosa), which features orange blossoms that provide excellent nectar for butterflies. In addition, the plants are an important larval food for monarch butterflies. 2 to 3 feet tall; Zones 4 to 9. Three plants
Rain Garden for Shade
Placing a rain garden in full shade is not recommended; partial shade is best.
Shade Rain Garden Plant List
In the center, plant #1 to #6. For the drier, outer edge, plant #7 to #14.
- Rhododendrons, especially cold-hardy native rhodora (Rhododendron canadense), which like damp soil and partial sun. They will bloom profusely in the spring. 2 to 4 feet tall and wide; Zones 3 to 6. Two plants.
- Winterberry (Ilex verticillata), which needs one male plant to act as a pollinator, along with the females, if you want a crop of colorful red berries. For this garden size, choose from dwarf cultivars. 3 to 5 feet tall; Zones 3 to 9. Two plants.
- Cardinal flower (Lobelia cardinalis), which grows well in sun or partial shade. It has rich red flowers in late summer. 2 to 3 feet tall; Zones 3 to 9. Six plants.
- Pink turtlehead (Chelone lyonii), which is a trouble-free perennial that doesn’t mind wet feet. It blooms in the late summer to early fall. 2 to 4 feet tall; Zones 3 to 8. Seven plants.
- Purple meadow rue (Thalictrum dasycarpum), which loves a damp spot in partial shade. It can get quite tall and has clouds of purple-tinged white blossoms in summer. 3 to 6 feet tall; Zones 5 to 9. Two plants.
- Wild columbines (Aquilegia canadensis), which are an important source of nectar for hummingbirds and butterflies and thus will draw them to your rain garden. They produce their bicolor red and yellow blossoms in late spring. 1 to 3 feet tall; Zones 3 to 8. Five plants.
- Arrowwood (Viburnum dentatum), which is a nicely rounded shrub with glossy leaves and dark blue berries. It has creamywhite blossoms in late spring and colorful fall foliage. 6 to 10 feet tall and wide; Zones 3 to 8. One plant.
- Dwarf fothergilla (Fothergilla gardenii), which has fragrant white flowers that appear before the plant leafs out in the spring. The foliage becomes a neat, crimson mound in the fall. 3 feet tall and wide; Zones 5 to 9. One plant.
- Common bearberry (Arctostaphylos uva-ursi), which is a rugged evergreen ground cover in the heath family. It has white flowers in spring and red berries in late summer. 3 to 8 inches tall, spreading to between 2 and 4 feet wide; Zones 2 to 6. Five plants.
- Coral bells (Heuchera sanguinea), which are colorful foliage plants that send up tall spikes of tiny red, pink, or white flowers in late spring. 6 to 12 inches high and wide; Zones 3 to 8. Seven plants.
- Foam flower (Tiarella cordifolia), which is a deer-resistant plant with white flowers in spring. (Heuchera and Tiarella have been crossed to create a hybrid genus called Heucherella which combines the gorgeous foliage of heucheras with the showy flowers of tiarellas—look for this one!) 5 to 12 inches tall; Zones 3 to 7. Five plants.
- Jacob’s ladder (Polemonium reptans), which is a low-growing, spreading perennial with clusters of light-blue flowers. 8 to 12 inches tall; Zones 3 to 8. Three plants.
- Zigzag goldenrod (Solidago flexicaulis), which bears golden yellow flowers in the fall. 2 feet tall and wide; Zones 3 to 8. Three plants.
- Spotted geranium (Geranium maculatum), which has dainty, pinkish-purple flowers that bloom above the mound of lobed leaves in the spring and often again in the fall. 1 to 2 feet tall; Zones 4 to 8. Six plants.
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