The 100-square-foot rain garden that Eric and Lusana Cacioppo dug in their Melrose Park yard two years ago works like a charm. No more waterlogged lawn, no more standing water and, voila, far, far fewer mosquitoes. The garden is thriving (and thrived even through the great drought of 2005). The goldenrod is so happy, it’s getting too fat and bushy and will have to be thinned. That tends to happen with rain garden plants: They like the life.
What is a rain garden? It’s not a water garden. Not a puddle (that’s what the Cacioppos had before, kept wet not only by rain but by underground springs).
A rain garden is more like a sponge.
It’s based on the idea that the right plants, given time to do so, can soak up vast quantities of water. They can absorb excess ground water, or — if you just hold rainwater around their roots for a while, less than 24 hours — they’ll quaff it happily.
Holding the water is a pie-plate-shaped depression a few inches to a couple of feet deep, filled with a mixture of soil, sand and compost, planted mainly with native Midwestern plants and mulched.
The result can be a powerful thing. Not only can it transform a water-laden spot. It can be a way for homeowners to take charge of some of the torrents of rainwater that otherwise wash off driveways, streets and lawns to overwhelm storm sewers, back up into basements and carry pollutants into waterways — “all the way to the Gulf of Mexico,” says Sue Cubberly, whose Chicago-based firm, Rain Garden Network (consisting of her and her husband, Frank Maldonado), designed and installed the garden.
Sprinkle less
A rain garden is a way to use the water that falls naturally on your garden, instead of sprinkling with water that, after it fell as rain, went all the way out the sewers and through a treatment plant before it was pumped back to come out of your hose.
It’s a way to spend less time watering and more time sitting on the patio. If you pay by the gallon, it’s a way to save money on water. It helps return to the ground water we have been pumping out to flush toilets and water lawns. It can turn a terrible waste into something wonderful. And it’s so simple that just about any gardener can do it.
When Eric Cacioppo gets compliments on the bed of purple coneflower, cup plant, prairie dock, bee balm, switchgrass, blue flag iris and Culver’s root, he seizes the chance to explain the rain garden and the stormwater problem.
The Cacioppos were so pleased with rain garden No. 1 that they dug and planted a second one to handle the outflow from their sump pump and are planning another in the front yard.
That’s another thing that tends to happen: Once you notice how water flows around your land — much of it wasted — you see opportunities everywhere.
Cubberly and Maldonado started small, with a modest rain garden in the space between the garage and the side fence on a standard Chicago lot on the Northwest Side. Then they realized that by channeling the water from a garage gutter through a small rock-lined channel to another rain garden, they could dry out a corner enough to grow tomatoes. That led to rain barrels, a devotion to native plants and a business designing rain gardens and proselytizing for them. Now the pair is busy removing half the front lawn to make another one.
Cubberly will plant it with the native species she has come to love. They are recommended for rain gardens because of their large, deep, absorbent root systems and because they are so well adapted to Midwestern conditions that they easily survive bitter winters and choking summers while requiring little attention.
As the Cacioppos’ once-soaked lawn shows, turf grass has a scant root system to take up water. But prairie plants guzzle it.
Black-eyed Susan, butterfly weed and spiderwort are among the plants Mea Blauer, resource conservationist with the Soil and Water Conservation District of Lake County, planted in the rain garden in her Waukegan back yard. “There’s so much color and so much variety,” she says. “I weeded them the first three years, but I didn’t use any pesticides or fertilizers.” Now they have filled in and shoulder weeds aside.
Cubberly will mass plants, cottage gardenlike, and accept that she will need to police them a bit to keep them in bounds. “In front of my house I want something that looks like a garden,” Maldonado says.
Beyond natives
You don’t have to use all native plants, Cubberly says, though they give you the most bang for your water-saving buck. You could tuck other perennials or even annuals around the edges. A rain garden easily could be just an area within a larger garden.
A rain garden can be as formal as you please, says landscape architect Marcus de la Fleur. But the more formal it is, the more you will have to fuss with it.
In front of de la Fleur’s own yellow house in Elmhurst, prairie plants are interspersed casually as they would be in nature. There are lots of prairie grasses — “the backbone of the rain garden,” he says, because they have the largest root systems.
His little patch of prairie does attract attention (that, and the green roof over his front porch). But “people walk by and realize that things the way they look are that way for a very particular reason,” he says. “I get tons of questions.”
De la Fleur leaps at the opportunity to explain not only the rain garden, but the way it fits into a whole system through which he aims to take responsibility for every drop of water that falls on the lot: the rain barrels (painted yellow, with butterflies, to match the house); the swale — a long ditch lined with rocks — that collects and holds more runoff; the old cistern he has cleaned out and reconnected to store rainwater for garden use; the patio made of reclaimed pavers between which water can soak into the ground; the turf parking space with a special base of gravel and sand for drainage.
De la Fleur’s Elmhurst firm, Conservation Design Forum, designs stormwater-handling landscapes for businesses and institutions. But he hopes his house and his rain garden by the sidewalk will help raise the consciousness of home gardeners about rainwater and how to create landscapes that make the most of it. When you look at a rain garden, he says, “you’re not just looking at something decorative and beautiful, but it actually has a purpose, it actually does something.”
Making a difference
Doing something about stormwater is why governments and environmentalists nationwide are trying to interest homeowners in rain gardens. The problem is getting harder to handle as ever more land is paved or covered with buildings, leaving less land for rain to soak into.
In Chicago, with its combined sewers, large quantities of clean rainwater are combined with smaller amounts of waste from kitchen sinks, washing machines and toilets, and it all has to be treated (unless the sewers are overwhelmed and it is flushed into Lake Michigan). So the City of Chicago and the State of Illinois are officially encouraging rain gardens and other methods of keeping the rainwater clean.
Making a rain garden takes a little thought — you have to do a little math, to get it the right size, and a little planning, to make sure gravity moves the water where you want it to go. But plenty of advice is available from municipalities and organizations that want to encourage as many people as possible to make rain gardens.
“If there’s one person who does it, that’s a drop in the bucket,” says de la Fleur. “But if everyone on the block does it, that can make a real difference.”
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How to make a rain garden
Here are some basic steps toward creating a rain garden. Government and environmental sources (see accompanying story) offer detailed instructions. The key point: Plan well before you step on the shovel.
– Pick your spot: Figure out where your water supply would come from, says Sue Cubberly of the Rain Garden Network. Remember that water flows down and that even on unpaved surfaces, such as lawn, it needs awhile to sink into the ground. If more water is falling from the sky than can be immediately absorbed, it will run off.
The next time it rains, take an umbrella and do a walk-around. You most likely will be surprised at the number of spots where you can catch water: rainwater that flows down alley blacktop toward a sewer drain; that washes over the lawn and then down the driveway; or that rolls off high spots in the garden before it has a chance to sink in.
– Do the math: Any amount of rain garden is a start. But if you want to absorb all the water from a gutter downspout, for instance, you’ll need to calculate how much water flows through that spout from the area of roof that it drains. That will tell you how wide and deep the garden needs to be to handle, for instance, a 1-inch rainfall. You still will have to think about where surplus water would go if we had a monsoon.
– Check your soil: Different soils drain at different rates; loamy soil drains better than clay soil. As with any garden project, it’s a good idea to get the soil professionally tested. But you can get a very rough idea of how well your soil drains by digging a bucket-size hole, filling it with water and watching how long it takes to drain away. The ideal for a rain garden is to match your garden’s size to your water source and soil type so it is big enough to hold water long enough to be absorbed by plants’ roots, but be gone in 24 hours.
– Plan your planting: Choose Midwestern native plants that suit your basic sun and soil conditions. (For lists of Midwestern natives, see sources in accompanying story.) Make sure you include plenty of prairie grasses. You can casually mix it up. Or go formal — arrange the plants in masses, perhaps with the tallest in the center. But remember that you will have to do some tending to keep the plants that like your site best from crowding the others out.
– Sharpen your shovel: It really helps. Then mark out the shape of the rain garden. Dig sloped sides and a flat bottom, like a pie plate, Cubberly says.
– Fill it up: Mix sand, compost and soil — in roughly equal parts — to fill the depression. With leftover soil from the hole you’ve dug, fill in a low spot or create berms that encourage water to flow toward the rain garden — not toward the storm drains. Also make sure the edge of the sidewalk or adjoining turf is higher than the surface of the rain garden so that rainwater flows into it.
– Plant: It’s best to start with small plants; seeds take too long to develop enough roots. As you plant, be careful not to compact the soil mix. Mulch to keep in moisture and discourage weeds. Water only for the first two or three weeks until the plants can fend for themselves. For the first couple of seasons, you will have to do some weeding until plants are lush enough to crowd out weeds. Renew mulch each year.
— Beth Botts
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Learn more
Here are some sources of information on how to plan and install a rain garden.
Rain Garden Network: This Chicago firm installs rain gardens and has a Web site with much information and good links. An information packet, including waterproof laminated instructions, a plant list and maintenance advice, is $20. Sue Cubberly also consults with institutions, governments and homeowners associations about larger rain gardens.
Call 773-774-5333, see www.raingardennetwork.com.
City of Chicago: The Department of Environment has a brochure that can be downloaded. Go to www.cityofchicago.org/environment; click on “Publications” at the very bottom of the page and scroll down to “Rain Garden Brochure.”
Or call 312-743-WATER (312-743-9283).
Wisconsin Department of Natural Resources: This agency’s excellent Web site has much guidance, many links, an instruction manual (with suggested planting plans) that can be printed out and ideas for involving kids. See www.dnr.state.wi.us/org/water/wm/nps/rg/.
Rain Gardens of West Michigan: A Grand Rapids-based coalition of environmental groups has advice and instructions at www.raingardens.org.
Friends of Bassett Creek: The Web site of this Minneapolis river conservation group has a good short primer and plant list: www.infinetivity.com/(tilde)stack/rain/index.htm
Maplewood, Minn.: This city’s Web site offers ample information, including suggestions for different types of sites and plantings: www.maplewoodmn.govoffice.com/index.asp %% ype=B(underscore)BASIC&SEC=%7BF2C03470-D6B5-4572-98F0-F79819643C2A%7D
— Beth Botts
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ebotts@tribune.com
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