Reclaim Your Rain: Rain Gardens for Home Landscapes
Have you ever been frustrated by having to water your lawn
only days after a rainstorm? Where does all that water go? Add
in the watering restrictions, and it makes maintaining that
green lawn even more challenging. It may be time to consider
replacing some of your grass with a rain garden.
Rain gardens are landscaped areas designed to collect and utilize
rainwater. They are a great way to reclaim rainwater from a
roof downspout or driveway. Rain gardens allow more water from
rain to soak into the ground to water plants and create a beautiful,
low-maintenance landscaped bed. Typically about 30 percent more
water from a rain soaks into the ground in a rain garden than
in an equivalent area of lawn.
Rain gardens reduce stormwater runoff that carries pollutants
from fertilizers and pesticides and debris washing from lawns
and driveways into nearby rivers, lakes or streams. They also
prevent damage to stream banks and reduce the risk of local
flooding. In addition to being beautiful, they can provide valuable
habitat to many birds and butterflies.
How Do Rain Gardens Work?
A rain garden collects stormwater, filters it through soils
and plants and allows it to soak into the ground. A rain garden
receives runoff water from lawns as well as rooftops or other
hard surfaces such as driveways. The rain garden holds the water
on the landscape so that it can soak into the ground instead
of flowing into a street and down a storm drain. The plants,
mulch and soil in a rain garden combine natural physical, biological
and chemical processes to remove pollutants from runoff. Many
pollutants will be filtered out and break down in the soil over
time.
Where Are the Best Places to Locate Rain Gardens in the Landscape
Rain gardens are best located in low areas if the yard where
runoff tends to flow. While they should not be built next to
a building’s foundations, rain gardens located near to
impervious surface such as driveways, patios and sidewalks can
easily capture the runoff from these areas.
A rain garden should be located at least 10 feet from the foundation
of the house or other building. Sites with more than a 12 percent
slope (an elevation change of 12 feet down per 100 feet in length)
may not be suitable for rain gardens. Further, if you have a
septic system, avoid planting a rain garden over top of the
system.
What Plants Should You Use?
Finding plants for your rain garden is not difficult. Many native
plants, available at your nearest Pike Family Nursery, are well-suited
for your rain garden. Here are some suggested native plants:
| Trees |
| Red Maple |
Acer rubrum |
| Black Gum |
Nyssa sylvatica |
| Willow Oak |
Quercus phellos |
| Bald Cypress |
Taxodium distichum |
| River Birch |
Betula nigra |
| Musclewood / American Hornbeam |
Carpinus caroliniana |
| Green Ash |
Fraxinus pennsylvanica |
| Sweetbay Magnolia |
Magnolia virginiana |
| Shrubs |
| Virginia Sweetspire |
Itea virginica |
| Summersweet Clethra |
Clethra alnifolia |
| Common Winterberry/Winterberry Holly |
Ilex verticillata |
| Buttonbush |
Cephalanthus occidentalis |
| River Birch |
Betula nigra |
| American Beautyberry |
Callicarpa americana |
| St. John’s Wort |
Hypericum fasciculatum |
| Perennials, Grasses and Groundcovers |
| New England Aster |
Aster novae-angliae |
| Broadleaf Uniola/Indian Woodoats |
Chasmanthium latifolium |
| Joe-Pye Weed |
Eupatorium fistulosum |
| Swamp Sunflower |
Helianthus angustifolius |
| Scarlet Rosemallow/Swamp Hibiscus |
Hibiscus coccineus |
| Cardinal Flower |
Lobelia cardinalis |
| Cinnamon Fern |
Osmunda cinnamomea |
| Royal Fern |
Osmunda regalis |
| Switchgrass |
Panicum virgatum |
| Golden Ragwort |
Packera aurea |
| Ironweed |
Vernonia noveboracensis |
| Yellow Stargrass |
Hypoxis spp. |
| Swamp Milkweed |
Asclepias incarnata |
| Asters |
Aster spp. |
| Violets |
Viola spp. |
| Broomsedge |
Andropogon virginicus |
| Narrowleaf Dragonhead |
Physotegia angustifolia |
| Blackeyed Susan |
Rudbeckia hirta |
| Loosestrife |
Lythrum spp. |
| Red Columbine |
Aquilegia canadensis |
| Clubed Begonia |
Begonia cucullata |
How to Create a Rain Garden
1. Locate a rain garden in natural depressions in the landscape
near a downspout of the home.
2. Use rope or garden hose to lay out the boundary of the
rain garden in a curvy in shape with the longest length perpendicular
to the slope of the land.
3. The rain garden should be designed to hold about 6”
of water above the ground surface.
• Ideally, locate the rain garden in such a way that
a low berm on the downhill side of the rain garden will hold
back the appropriate amount of water. A berm is a small earthen
dam, no more than 12” high.
• The bottom of the rain garden should be as level as
possible, so some minor grading may be necessary.
4. A shallow swale or corrugated drain pipe (buried or above
ground) will channel runoff from the roof downspout or paved
surface to the rain garden.
5. The soil in the rain garden should be a loose, sandy organic
soil that allows water to quickly soak into the ground to nourish
plant roots and recharge the groundwater. A general rule-of-thumb
is to have a soil that soaks in about one inch of water per
hour. The following steps will help to achieve this:
• Mix organic matter into the soil within the rain garden
by spreading 2 to 4 inches of compost over the area and mixing
the organic matter in with the existing soil.
• If the soil is acidic (has a low pH), lime should also
be added to neutralize the pH of the soil.
• For soils with high clay content, it may be beneficial
to remove about 1-2 feet of the soil and replace it with a more
porous “rain garden soil.” A soil mix suitable for
rain gardens is a mix of 50-60 percent sand, 20-30 percent topsoil,
and 20-30 percent compost. The clay content in the rain garden
soil replacement mix should be no more than 10 percent.
6. Establish a grass or groundcover border along the upper
edge of the rain garden to slow down the runoff water as it
enters the rain garden. Do the same over the berm to stabilize
it as a border of the rain garden.
7. Plant drought tolerant, wet tolerant, hardy plants. A mix
of ornamental grasses, shrubs and self-seeding perennials are
good choices. See list above.
8. Once plants are in place, cover the rain garden with a
3” layer of mulch. Shredded hardwood is a good choice
since it is less likely to float away.
9. Remove weeds on a regular basis and replenish mulch as
needed.
10. IMPORTANT NOTE: Plan on providing an “overflow”
path for water to take if it keeps raining after the rain garden
fills up. This path should be stabilized with a hardy grass
or groundcover
A rain garden can be the beginning of a more natural landscape
for a homeowner. A more natural landscape can combine beauty
with less maintenance and less need for chemicals. There is
also a great deal of satisfaction from knowing that the landscape
is keeping pollutants out of streams and lakes close by. To
learn more about rain gardens or to find photos of demonstration
sites, visit www.cleanwatercampaign.com
or call 404-463-3259.
(Special thanks to Dr. Rose Mary Seymour of the University
of Georgia Cooperative Extension Service Griffin Office and
Alfred Vick, Ecos Environmental Design, Inc..)
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