This guide is for residential use only. For regulated stormwater BMPs in St. Louis County, please refer to the MSD BMP Toolbox. In other areas, check your municipal regulations.
Now let’s start planning! To make it as simple as possible, our Rain Garden Guide will walk you through the basics from location to soil type to long-term maintenance.
STEP 2: DESIGN
Create a template using graph paper to draw your design to scale, including the area for your berm, indicating your house location and water source. To design your garden, find inspiration from our templates or browse our Rain Garden Gallery.
Powered by the Missouri Botanical Gardens, our Plant Selector will help you choose plants best suited for your rain garden.
Some things to keep in mind: Native plants create microhabitats and increase biodiversity. Their deep root systems aid infiltration, and both roots and leaves remove pollutants. Learn more about the power of native species at www.grownative.org.
Other considerations when choosing plants include, sun exposure, soil type and water tolerance.
Plants are generally divided into three categories: full sun, partial sun/shade, and shade. Most rain gardens do best with full or partial sun.
- Plants needing full sun require six or more hours of direct sunlight each day.
- Full shade plants require less than three hours of direct sunlight, with filtered sunlight for the rest of the day.
- Partial sun and partial shade plants need between three and six hours of direct sunlight per day and may be sensitive to whether it’s morning or afternoon sun.
When it comes to soil, plants are sensitive to the water capacity, acidity or alkalinity, pH and mineral content…another great reason to integrate native plants into your design-- they’re already adapted to the local soils. For best results, knowing your soil type will help you choose the right plant mix. If you want to get a soil analysis, you can get instructions on how to obtain one here or browse additional services here.
Mulch & Hardscaping
Mulch will help keep weeds down and protect the soil. A wide range of colors and textures are available by the bag or in bulk from local nurseries or home improvement stores, but remember this is a rain garden, so choose heavier mulches or even rock that won’t float or wash away when the garden takes on water.
Hardscaping is garden detail other than plants and mulch, like rocks, sculpture, or drainpipe. There are two particular areas that may need hardscaping:
- If you direct or pipe a downspout without using a pop-up drain, use rock to reinforce the area where water comes into the garden to prevent erosion.
- If the garden is small relative to the volume of water entering it, then you may need to notch the berm to direct where you want the overflow to go. Use rock to keep the notch from eroding
It’s also a great way to add structure and interest to your garden. Use it to create a clean, definitive border between the yard and the garden or add an interesting focal point, so keep it in mind as you plan.