The Benefits of Putting in a Rain Garden

Jun 14, 2018

Gardens not only beautify our lives, they benefit pollinators and can even slow runoff and clean the water.

In this week's episode of Wildlife Matters, the Masked Biologist talks about his own experience with putting in a rain garden.

Four years ago, we decided to put in a rain garden. We have a spot in our front yard that gathers rainwater; a depression that would lend itself well to this kind of landscaping. If you are not familiar with the rain garden concept, it is not a spot that holds water, like a pond or a water garden. It is a spot where rainwater gathers or collects, where you can plant a variety of grasses and flowers to slow down the runoff and help it soak into the ground.

The rain that falls on a city like Rhinelander hits a lot of hard, nonabsorbent areas, what we call impervious surfaces. It runs off roofs, parking lots, driveways, and sidewalks into gutters and storm drains, where it rushes into local lakes, streams, and rivers. When it leaves, it takes road salt, motor oil, pollutants, fertilizers, and particulates along with it. Capturing and slowing this runoff reduces the amount of transported material, improving water quality. Keeping rainwater also reduces the need to water lawns and flowers, and helps recharge what groundwater we have in the area.

Rain gardens are pretty straightforward, at least on the surface. You select a variety of grasses and flowers that grow well in your area, are not considered invasive species, and benefit birds, butterflies, or other pollinator species. I admit, I have been a little hesitant to bring this kind of management into my front yard because I know there is a Midwest culture that makes people look at this as an ugly weed patch. People love their close-cut manicured green lawns and tidy yards. They spray and pull the plants growing in their gardens, then plant new flowers in nice tidy rows. It seems that as concerns about butterflies and pollinators have arisen, people have come to appreciate that there are some beautiful, beneficial plants that are treated as weeds but are very important to the ecosystem.

Take milkweed for example. This “weed” is extremely important for the life cycle of the monarch butterfly. Monarchs lay their eggs on milkweed plants. Upon hatching, the caterpillars go straight to work, chomping on leaves day and night. When these caterpillars eventually become butterflies, the milkweed they had ingested makes them toxic. Anything that tries to eat a monarch butterfly is going to end up very sick, and won’t eat another one. Of course, the flowers provide nectar for a variety of pollinating insects as well.

We sought the advice of local professionals and got help from Hanson’s garden nursery where we bought our plants. We selected a variety of bunch grasses and flowers that would bloom and grow at different times of the year. Our prairie smoke leads the way as soon as the frost leaves the ground, followed by blue flag iris, butterfly milkweed, and a couple other flowers. The sunflowers and black-eyed Susans end out the fall until the killing frost hits. At the end of the season, we simply mow over the dead flowers, spreading the seeds for next year’s crop.

As the first season progressed, it became clear that we had chosen the right spot for the garden, but there was so much runoff that we could use another buffer in our system. So, we dug in a cracked water garden liner and built a first-stage garden with wetland sedges and mints that help hold the initial rush of water and allow some of the runoff from our roof and deck to percolate underground toward the main garden.

Gardening is the number one outdoor recreation activity in the United States. You can take it a step further; be a habitat and runoff manager while enjoying a great hobby that gets you outside. This kind of gardening is an easy way to do a little something to help make a difference to insect and wildlife species that share our habitat with us.

Striving to make new things familiar and familiar things new, this is the Masked Biologist coming to you from the heart of Wisconsin’s great Northwoods.