Rain Gardens

Do you have a problem area in your yard or on your property?
Perhaps it is a low-lying area where water collects, where there is erosion due to storm water, an area where nothing will grow, water near your foundation, or just an unattractive, hard to maintain ditch. Are you environmentally conscious, wanting to use practices in your landscape that will promote a healthier environment with minimal effort?

Well, you might want to consider this low cost solution for all of these problems that is environmentally friendly – a Rain Garden. Rain Gardens are becoming more widely used and are growing in popularity.

This has probably (hopefully) prompted you to ask “What is a Rain Garden?”
A Rain Garden by definition is a garden that captures rain water runoff from roofs, driveways, lawn, and roads. When landscaped, they provide an attractive bed which fills with a few inches of water that slowly filters into the ground. They are 30% more effective than a patch of conventional lawn at returning water into the ground.

Benefits of Rain Gardens:
Retaining and filtering storm water runoff helps prevent pollutants such as excess fertilizer from lawns or roadway oil residue from entering storm sewers that empty into nearby streams, lakes, and, in the Farmville area, eventually the Chesapeake Bay.
Erosion in the immediate area and erosion in local stream banks from rushing storm water is lessened as the water is captured and slowed.
The water works through the layers of mulch and soil, and is filtered in the process. So, when the water enters the groundwater table, its quality is improved by the filtering and contains fewer pollutants.
Streams benefit from a more gradual increase of filtered water, helping to sustain water flow during drier spells and creating healthier streams.
Let’s not forget the beauty and curb appeal the Rain Garden will bring to your property! Where once there was hard packed dirt or an unattractive, unmanageable ditch, beauty can bloom while helping the environment and providing wildlife habitat.

Where to place your Rain Garden:
Survey your landscape. The Rain Garden should be at least 10 feet from building foundations to prevent water seeping into structures. You should also place it less than 30 feet from downspouts for ease in capturing roof runoff. Your Rain Garden should be a part of your overall landscape design that you will enjoy.
Rain Gardens should not be placed over septic systems.
Do not place a Rain Garden in a low lying area where water already ponds. While this is tempting, standing water in an area indicates poor infiltration. It is better to place your Rain Garden where the standing water will flow and infiltrate into the soil.
Digging is easier and the Rain Garden will prosper better in full or partial sun – not under a big tree. Tree roots impair the digging process and those roots could be damaged, thus endangering the tree’s health. Your flowers, shrubs, and bulbs will need sufficient sunlight to flourish.
Digging is easier in a flatter part of a yard rather than on a slope. A slope requires more measuring and deeper digging. However, it is certainly possible to place a Rain Garden in a sloped area with the proper preparation and planning.
Consider your entire landscape and slope, taking advantage of any natural slope to route water to your Rain Garden. Give thought to the use of your yard and how your Rain Garden will impact an area used for play or lend beauty to a patio or deck.

Size formula:
The size of your Rain Garden depends on the area of drainage (what area you hope to capture runoff from), the percentage of runoff you hope to capture, and the type of soil in your landscape. Formulas and more information can be found in the sources listed on the Heart of Virginia Master Gardener website. The website will be given in just a little bit so gather your pen and paper to be ready.

Soil formula:
A good soil mixture is 20% leaf mulch, 50% sandy soil, and 30% topsoil. While Rain Garden mix is available commercially it is easy enough to make your own mix if you have a little area in which to do it, some old leaves (fall is here), some topsoil, and sand which can be purchased locally if necessary.
Other important specifications for your Rain Garden:
Other than plant selection, there seem to be few hard and fast design rules for size, shape, or color schemes, so you can be creative and use your imagination.

Plant suggestions:
You will need to use care in your plant selections. Your plants need to be both drought tolerant and moisture tolerant because they will experience times of standing water during rainy periods and drought in dry times. Having said this, you have a wide range of choices from grasses to trees, shrubs to bulbs. Bulbs will prosper around the outer perimeter, where they will not get too much water that could cause rot. You can choose a theme of native flowers or build a habitat for birds and butterflies. Try to plan your garden for year round beauty that will provide seasonal color and winter structure. For example, Red Twig Dogwood bushes can provide year long color and structure.
Got your pen and paper? Check the Virginia Cooperative Extension Heart of Virginia Master Gardener website at www.hovmg.org for this informational message, links to Rain Garden information, and other resources. There will be a demonstration garden coming soon in Farmville that will be posted on the website when installation is complete.
Don’t stop here. Rain Gardens can work in business landscaping too. Encourage businesses to capture runoff from their parking lots as well as their roofs.

Sources and links:
Rain Garden General Information
http://www.dof.virginia.gov//rfb/rain-gardens.shtml
http://www.dnr.state.wi.us/org/water/wm/nps/rg
http://www.raingardens.org/
clean-water.uwex.edu/pubs/raingarden
www.mninter.net/~stack/rain
www.consciouschoice.com/environs/raingardens1405.html
natsci.edgewood.edu/wingra/management/raingardens
unisci.com/stories/20022/0425026.htm
www.duluthstreams.org/citizen/wet_garden.html
chicagowildernessmag.org/issues/spring2001/raingardens.html
www.epa.gov/OWOW/info/NewsNotes/issue42/urbrnf.html
www.weemscreek.org/proj-mine-raingarden.html
www.appliedeco.com/RainGardens.cfm

Rain Gardens: A household way to improve water quality in your community. A University of Wisconsin – Extension and Wisconsin Department of Natural Resources publication.

Rain Gardens: A how-to manual for homeowners. A University of Wisconsin – Extension and Wisconsin Department of Natural Resources publication.
www.dnr.state.wi.us/org/water/wm/dsfm/shore/documents/rgmanual.pdf

Plant Suggestions
http://www.partnershipforraingardens.com/plant_list.htm
http://www.wildflower.org/i
http://www.prairienursery.com/
http://www.for-wild.org/

Written by members of the Heart of Virginia Master Gardeners

posted 3/1/07