RAIN GARDENS These educational materials are the courtesy of Compiled here by Liz Hugel / GINLC Education Committee

What is a rain garden? A rain garden is an attractive landscaping feature planted with perennial native plants. It is a bowl-shaped garden, designed to absorb stormwater run-off from impervious surfaces such as roofs and parking lots. Rain gardens can be small, formal, home- owner style gardens, large complex bioretention gardens, or anywhere in between.

Why do we need rain gardens? Rain is natural; stormwater isn't. Government studies have shown that up to 70% of the pollution in our streams, rivers and lakes is carried there by stormwater. Although most people never think about stormwater, about half of the pollution that stormwater carries comes from things we do in our yards and gardens! Planting a rain garden may seem like a small thing, but if you calculate the amount of rain that runs off your roof, you would be very surprised. That rain is supposed to soak into the ground, but instead heads down the street to the storm drain, carrying pollution with it. Keeping rain where it falls, by putting it into a beautiful rain garden, is a natural solution. You not only get a lovely garden out of it, you have the added benefit of helping protect our rivers, streams and lakes from stormwater pollution. You can be part of a beautiful solution!

What Makes a Garden a Rain Garden? A rain garden resembles a regular perennial garden in many ways. It is designed with deep-rooted plants that come back year after year; it is pretty to look at; it often has lovely flowers, grasses, trees and shrubs.

Qualities that make a rain garden unique. Rain Gardens have a ponding area, but they are not ponds. They often are planted with wetland plants, but they are not wetlands (although you can design a rain garden that mimics a wetland). The garden absorbs and filters rain that would otherwise run off your property and down the storm drain. This stormwater runoff usually comes from an impervious surface that rain cannot soak into, such as a roof or parking lot, or even a lawn. Many of the plants in the garden are native to the region, and have extensive deep roots that help the garden absorb rain. The native plants do not need special attention once they are established. There is a bowl-shaped dip in the garden, which holds the rain while it soaks into the soil. The garden bed is prepared or sometimes replaced to a depth of two feet in order to de-compact the soils and make the garden able to absorb water.

Benefits of Rain Gardens Rain gardens are lovely landscaping features. Rain garden plants create wildlife habitat and attract butterflies, birds, and other wildlife. Rain gardens can save you money. They don't need to be fertilized or sprayed, only weeded and mulched. They reduce the amount of lawn you have to maintain. This makes your yard a healthier place for children and pets. A rain garden on your property makes you part of a solution to stormwater pollution. Rain gardens can potentially absorb hundreds of gallons of rain that would otherwise wash pollution down the street and into the nearest river, stream, or lake. Even small rain gardens can absorb a lot of rain. A rain garden can be part of a stormwater reduction plan to help solve problems of combined sewer overflows (CSOs).

Benefits of Rain Gardens cont Rain gardens can actually remove many of the common pollutants in stormwater. (fertilizers, pesticides, oil residue ) Rain gardens are low maintenance. Once established, they require no fertilizer, watering, or mowing. A once a year cleanup, addition of shredded hardwood mulch to keep the surface moist and tidy, and removal of weeds and invasive species are all that are required. Rain gardens can contribute to groundwater recharge, a natural process that is interrupted by soil compaction and hard surfaces created during development and building. A rain garden project can educate the public about the problems that stormwater runoff creates, while giving people a beautiful solution. A rain garden project can be part of the educational toolbox used by a community stormwater education team.

Benefits of Rain Gardens cont Reduce mowing –Lawn mowing contributes greatly to the ozone problem. Engines are inefficient at reducing pollution. In fact, using a gasoline-powered lawn mower for one hour generates the same amount of air pollution as driving a car for forty hours. A gasoline-powered weed eater operated for one hour is even worse as it generates pollution equivalent to driving a car for sixty hours.

How much does it cost to build a rain garden? Rain gardens cost no more than regular flower gardens. The cost elements are the flowers, the peat moss or compost that you add to the garden, plus any edging or walls that you might build. Flower costs are a function of the size and number of flowers that you choose. A do-it-yourself homeowner who starts with mostly smaller plants might spend $ 2 to $4 per square foot.

Before Starting Choose The Right Place for Your Rain Garden A rain garden is one type of “bioretention”—a system of pond area, soil, plants and mulch that will retain water and soak it up instead of letting it run off of your property (even though your “pond” will be dry most of the time). So the most basic things are the “pond,” or depression into which water will flow, and the soils that will absorb the water. Your property has an existing drainage pattern (even though it may not be very noticeable), and it will usually be easiest to take advantage of that. Note the direction of runoff and low spots where water collects.

Hints for choosing a spot: Avoid creating a rain garden too close to building foundations; this may lead to a leaky basement. Be aware of rights of way and underground service lines or utilities. Re-directing the rain--there are a number of creative and attractive solutions if the rain doesn’t flow naturally to your chosen spot. If your land slopes, you can create a flat area for your rain garden in several ways. Black walnut trees growing by the garden may spell trouble, due to juglone, a chemical exuded from their roots. Don’t excavate an extensive rain garden under large trees.

Evaluate the Soil Soils vary greatly in fertility, drainage, and “pH” rating. Understand what kind of soils you are working with, and put in a garden suitable to the conditions you already have. Drainage is important Test your drainage! Design the Pond. Compacted Soils pH and Other Qualities

Prepare the Site –Define the Borders –How much soil is needed for replacement? –Improve the Soil –Grading the pond area

Develop a Design Tall Great Lakes Prairie Rain Garden For Sun (6+ hours of sunlight) and clay soils. Short Great Lakes Prairie Rain Garden For Sun (6+ hours of sunlight) and clay soils. Maplewood, Minnesota rain garden designs University of Wisconsin Extension Rain Garden Manual.University of Wisconsin Extension Rain Garden Manual.

Select the Plants: Use native plants in rain gardens Native plants can tough it out Native plants attract beautiful creatures Native plants have deep roots Obtain native plants Do not take your plants from the wild. Plan Ahead for Plant Needs

Plant the Garden & Rain Garden Care If it doesn't rain, water your plants until they are established. Break strong water flow. Mulch your rain garden. Weed regularly. Don't park or drive on your rain garden. Don't let sediment, soil, sand, or debris flow into your rain garden. Keep an eye on the plants.

Rain Barrels Saving Rain for a Sunny Day During a typical moderate storm of 1” of rain during a 24 hour period, over 700 gallons of water will run off the average roof, an impervious area of about 1,200 square feet. In one rainy day, your roof runoff could fill up fourteen bathtubs!

Rain Barrels 1)Your barrel must be made of “food quality” materials, so the water you save will remain uncontaminated. 2) Your rain barrel should NOT have a lid that easily comes off. This will insure that little creatures and little people will not be at risk of drowning in your rain barrel. 3) Your barrel should be safely screened so it doesn’t turn into a mosquito condo.