Why am I talking about rain gardens when it’s apparent we’re entering our dry time of the year? Hopefully it’ll serve to inspire some action to redo your landscape if you have areas prone to flooding from concrete drive or gutter run-off or just plain get too much rain. Think of it as a means to improve water quality, stem problems with soil erosion and deal effectively with excess drainage. Because I have low spots in my yard, I use French drains. They channel excess water through gravel and drain to a street ditch. Rain gardens, however, allow water to "pond", and as it percolates through the soil, it recharges groundwater. What results is a better method environmentally to process excess water.
Each rain garden site will have its own special considerations as to topography, soil type and permeability, amount of water accumulated and the speed with which that water enters the garden. Other factors: amount of light, temperature and size of drainage area.
You will need to provide a buffer strip of grass, appropriate area for ponding, organic mulch (absorbs excess water, retaining it for the plants) and an ideal fertile soil mix of 20% sand, 30% topsoil and 20% leaf mulch. Your rain garden can be planted with trees, shrubs and perennials attractive to wildlife, thus providing habitat with shelter and food.
Suggested trees: red maple, river birch, sweet gum, sourwood, pin oak, water oak, willow oak, bald cypress, sycamore and poplar. Suggested shrubs: serviceberry, red twig dogwood, witch hazel, winterberry holly, inkberry holly, pussy willow and bayberry. Suggested perennials: Joe Pye weed, daylilies, Japanese iris, cardinal flower, tall coneflower, ironweed, royal fern, cinnamon fern, Christmas fern, Lenten rose and blue lobelia. Your nurseryman can make other suggestions as well.