You may have wondered just what a rain garden is and why you might want one. Should everyone have a rain garden on their property? Is the purpose of a rain garden to display the water that falls from the sky, grow moisture loving plants, or something else? These are some of the questions I’ve heard from my clients and other gardeners, so let’s look at rain gardens in general so you can decide if this is a good idea for your landscape.
Rain gardens are created to catch excess water as it runs off of streets, driveways, and other landscaping. Why catch this runoff? There are several reasons:
1. For private homes it’s often helpful to channel water to places where it won’t cause flooding in basements or on walks and driveways. If water is directed into rain gardens, which are depressions designed to hold a larger volume of water while it soaks into the ground, then that water won’t collect in places where it can be a problem.
2. If the runoff from streets goes into the landscape, and percolates through the soil then it doesn’t go into storm drains. As there are more streets in suburbs and cities many areas have trouble with the large amount of storm water runoff and older drainage systems that can’t handle it all. So providing places where the rain can soak into the soil is helpful.
3. Driveways and roads accumulate particles of substances that come off of cars such as oil, rubber etc. If the rain that falls on these surfaces flows directly into ponds, lakes or streams those substances end up in water ways, but if the rain is allowed to first flow into rain gardens those things can filter into the soil instead.
4. A rain garden is also the natural way to handle an area that is often very wet. Instead of trying to grow lawn in such depressions, or change the natural flow of the land by trying to fill them up, creating a garden with plant that don’t mind being submerged can be a more sensible response.