Install a rain garden to beautify your garden and protect the environment at the same time. The purpose of a rain garden is to capture rainwater runoff, slowing it down so that it soaks gently into the soil instead of racing quickly off your property.
Undisturbed natural settings act like a great sponge: rain falls to the ground and slowly soaks into the soil, where it is filtered and cleaned, and where it eventually flows into rivers and groundwater.
But human-made settings are full of hard surfaces, like roofs, roads, sidewalks, and parking lots. When rain water lands on these surfaces, it cannot slowly infiltrate the ground. Instead, it quickly runs off and worsens water pollution.
During the next heavy rain, notice how fast the water gushes out of a drain pipe onto a driveway or into the road. That’s an example of runoff that sweeps pollutants like oil and trash into storm drains and then directly into our waterways. Even a sloped yard can increase runoff. The rain rushing downhill carries excess fertilizer into waterways. Flattened grass pointing downhill after a big rain is a sure sign of runoff..
Rain gardens recreate natural processes by giving rain water a chance to percolate more gently into the earth. They are typically full of gorgeous native plants and flowers, so they are beautiful as well as functional. The University of Georgia Center for Urban Agriculture suggests planting natives such as Joe Pye Weed (Eutrochium purpureum), Oak leaf hydrangea (Hyrangea quercifolia), and Summersweet (Clethra alnifolia)
in rain gardens.
It’s really important to locate a rain garden correctly. Look closely at your landscape to see where runoff goes. The right place for a rain garden might be next to your driveway or halfway down a gentle slope. Good drainage is crucial. Like a kitchen sink, you want the rain garden to hold water briefly then allow it to drain away. If the water doesn’t drain well, it will stagnate and attract mosquitoes. Install your rain garden away from the foundation of your house. Avoid septic lines and underground utilities—call your local utility for help identifying where to dig. Make sure the spot you choose is not too steep.
There’s a common misconception that rain gardens should be used to fill low, waterlogged spots in your landscape. You can improve these damp spots with what are called bog gardens, where the ground needs to stay wet (and which are the subject of another post). The soil in your rain garden, on the other hand, will alternate between wet and dry as water moves in and out, so be sure to select plants that tolerate extremes of moisture levels—think native species.
Here are some rain-garden-building basics:
- Direct runoff into your rain garden with a gutter downspout or a stone-lined waterway.
- Excavate a basin to the correct depth.
- You may need to install drain pipes under your rain garden, depending on the amount of water your garden receives.
- Line the bottom of the basin with gravel.
- Fill basin with properly draining soil.
- Plant, and then add mulch.
Fairfax County, Virginia, offers a very thorough guide to building a rain garden. Of course, another expert resource is Art of Stone. We can help you site, install, and build the perfect rain garden for Georgia residents. Contact us today!