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You Can Build A Rain Garden

A rain garden is an ordinary garden planted in a shallow depression and filled with native plants. Rain water from your downspout or driveway is directed to the garden, where it soaks into the ground instead of running into the street and then to the river.

A rain garden isn't a pond. The water usually soaks into the ground in a few hours. The garden is dry most of the time.

Digging a rain garden is easy. Professional landscapers need to know technical things to build commercial gardens, but home gardeners don't have such big volumes of water. Unless your lot is unusual, your rain garden won't need engineering.

You really can dig your own rain garden with only the directions below and the guts to go for it!


The most logical location for your rain garden is in an existing low spot in your
Place your garden where downspouts will drain into it, directing water with a
    shallow swale if necessary.
Place your rain garden at least 10 feet from your house or other building to
    keep water from seeping into and damaging the foundation.


It's simple! Follow three easy steps:

Start by digging a 4-8" depression with gradually sloping sides as large in
    circumference as you like. (A good rule of thumb is to size your garden at 30%
    of the area of the roof from which it will be collecting water.) A 4-8" depth will
    capture water and allow the garden to dry between rains.
Loosen the soil and mix in leaves or other organic matter.
If you like, add a raised edge, stones, or a few big rocks for visual interest.


A rain garden can have just grass or rocks in it, but native plants keep 30%
    more water in the garden. Of course you can buy plants, but talk with your
    neighbors first, to see if they have some that can be divided and shared.
To see southern Wisconsin's native plants and get lists of plants that thrive in
    rain gardens, click here.
Use plants rather than seeds to give the garden a strong start, minimize
    maintenance, and keep weeds down.
Plants that need medium to wet soil go in the deepest part. Plants that like drier
    soil go in shallower areas around the edges.
Add 3" of untreated, shredded hardwood mulch on all of the bare soil around
    the plants to prevent erosion while plants are getting established.


While your plants are establishing roots, water them about every other day.
    Continue for the first two to three weeks or until the plants are clearly growing
    and doing well.
When native plants need little or no additional watering once they're established.
Do not fertilize native plants! Fertilizer makes them grow too tall and fall over.
    It also stimulates weed growth, creating competition for your natives.

— Thanks to Sue Ellingson and Mid America Regional Council for the information above.


How To Install a Rain Garden

Seeing makes it easier! These folks get creative and add a rock waterway and little bridge, but those are just frills. The important parts are digging a shallow basin, loosening soil, and directing water to the garden.

Project Run-Down

Call the power company to mark
    utilities (free).
Choose a spot for your garden at
    least 10' from the house.
Remove sod. Loosen soil. Mix in
    leaves or other compost.
Dig the garden 3" to 6" deep.
Make a small mound at the edges.
Plant native plants.
Add 3" of mulch.
Aim a downspout at the garden.

What to plant? Where to get plants? How Many?

Ask a neighbor, local nursery, or La Crosse County Extension for names or starts of local native plants. Aster, daylily, iris, sedum, coneflower, artemisia and sedge are good rain garden plants. Stay away from plants that are too tall! And be careful with grass, which doesn't like to "get its feet wet." Put plants close together — one per square foot. Learn more about southern Wisconsin's native plants here.

For more detail, download this brochure from UW-Extension.

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