Rain Gardens

Bottle Gentian

Bottle Gentian

BY Rob Zimmer

Conserving the precious water resources of our area is important for many who live, work and play here in northeast Wisconsin.
There are things that each and every family, business and individual can do to help. One of the simplest and most effective is to install a rain garden on your property.

Maybe you’ve heard the term rain gardens before and have wondered exactly what this type of landscaping option is all about.
What is a rain garden?

Rain gardens are designed specifically using native plants, wildflowers and grasses in such a way as to capture and slowly filter precious rainwater back into our soil, rather than allowing it to run off and collect toxins that flow directly into our streams, lakes and rivers.

Rain gardens can be designed and created in a variety of shapes, sizes and forms, all specifically placed to capture run off from flat surfaces such as rooftops, driveways, roadways and parking lots.

As rain water flows over these surfaces, toxins and chemicals are picked up in the flow, creating a harmful mixture of salt, petroleums, chemical fertilizers, asphalt and other products that flow directly into the storm sewer and into area streams, lakes and rivers.

Capturing and slowly filtering this run off in rain gardens allows the natural processes of soil filtration to remove these toxins, allowing clear, fresh water to reach the water table below.

Big Bluestem Grass

Big Bluestem Grass

The size of a rain garden depends on the amount of area runoff is to be collected from. The larger the area, the larger the garden needs to be in order to fully capture and filter the resulting flow.

Why native?

Rain gardens are specifically designed using plants native to our area. This includes a combination of grasses, sedges, flowering plants, even small shrubs and trees depending upon the size of the garden.

Native plants are chosen because of their extensive root systems that make them the perfect natural filter.

Native plants naturally produce extremely deep and complex root systems, designed to support them through all weather conditions.

The root systems on some of our native grasses and forbs may reach 12 to 15 feet deep, allowing for deep penetration and slow, natural filtration of runoff.

Rain garden basics
Rain gardens are located in areas on properties where water naturally flows or collects. These areas can be expanded, deepened or sloped to maximize potential inflow.

Creating a shallow, sloped depression or bowl-shaped hollow, then planting with native wildflowers, grasses, sedges and shrubs, one can easily create an effective and environmentally friendly rain garden quickly and economically.

Native plants for rain gardens can be purchased from a variety of sources including many locations here in our area.

Stone Silo Prairie Gardens, De Pere, specializes in native plants, as does the Wild Ones native landscapers organization. Native plants can be found at a number of garden centers throughout the area as well, though selection varies and may be small.

What to plant
To create your rain garden, there are a number of fantastic plants available that bring beauty, color, texture, as well as the practical filtering function to your plant garden.

Blue Flag Iris

Blue Flag Iris

Native wildflowers such as purple coneflower, black-eyed Susan, cardinal flower, gentian, Joe-pye weed, ironweed, swamp milkweed, wild bergamot and others are great choices for rain garden creations.

Native grasses such as little bluestem, big bluestem, prairie dropseed, Indian grass and others make excellent additions as well.
For large rain gardens, shrubs such as native red dogwood, yellow dogwood, gray dogwood, ninebark, viburnum, willows and others are great choices to consider.

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