Now for the fun part – selecting your plants. Keep in mind that your rain garden, unlike a water garden, will be dry most of the time. The plants you select should be able to tolerate short periods of inundation, but not require constant, high moisture. Plants that are more moisture tolerant should be placed in the bottom of your garden. Plants which thrive in average or low moisture conditions should be placed further up in the garden, such as the side slopes.
Consider what you want your garden to look like – do you want color in the spring? summer? Do you want some plants that generate winter interest? Do you want a butterfly garden? Taking the time to plan plant type, size and placement will result in a more beautiful, easy to maintain rain garden. Don’t be afraid of grasses! Native grasses have extensive root systems, which really helps improve infiltration rates. Plus, they add interest in the winter time.
In shady gardens at least 50% sedges and ferns is a good rule of thumb for the wet zone.
To select plants, we suggest visiting a cool site sponsored by the Cincinnati Zoo and Botanical Gardens HERE. This comprehensive site links to the zoo’s recommendations for all plantings; scroll down to the perennials tab for more detailed descriptions.
How many plants you need will depend on the types of plant you select, however, dividing the square footage of the garden by 2.25 will tell you how many plants are needed if placed on 18-inch centers. Don’t worry about exact numbers, but planting in groups of 3 is another gardening rule of thumb.
Native species – that is, plant species that were present in this area before people were – are recommended because they thrive in local conditions, have deep root systems, and tolerate both spring rains and summer drought. Once they’re established, they’re low maintenance. Click HERE for a list of native plants. Most nurseries in the Greater Cincinnati area are carrying more and more native plants … call around or visit nurseries near you.