Rain Gardening is among the newest buzzwords at University of Illinois. The buzz is a response to another buzzword in the news: climate change.
Illinois' recently-retired state climatologist, Jim Angel, says one way climate change is affecting the Illinois landscape through more frequent torrential rains, as opposed to more frequent, lighter rains. These weather patterns can cause flooding and runoff. Any farmer with a bare field knows this is a problem, as nutrients or soil leech out of their field.
For a homeowner, runoff can be easily managed by a well-covered yard (grass, clover, groundcovers); but flooding is a different concern, with an unexpected solution for this soggy ground situation: rain gardens! A rain garden is usually bowl-shaped, intended to capture storm water and melting snow. These gardens slow down the surges of water caused by excess water events, and prevents them from entering into streams and sewage systems (which have to treat water before it can be released back into streams). Instead the water soaks back into the soil, and can even recharge ground water at a rate 30% better than a standard lawn does.
Rain gardens can be planned to capture runoff from your roof, roads, or parking lots. The Southern Lake Michigan Rain Garden Manual gives you further design principles like estimating size, testing soil, understanding slope, building the bed, garden designs, and plant lists.
There are considerations for which garden plants work best in a rain garden situation. Many of our favorite gardening plants would not be happy if their roots were perpetually wet, especially grasses. But some native Illinois plants thrive in times of flood and can tolerate some drought. These plants are well adapted to a rain garden. A rain garden plant must grow greater than six inches tall and be without lower basal leaves.
The Illinois-Indian Sea Grant put together a list of plants that would thrive in rain garden, native to Illinois and attract wildlife:
Columbine are a woodland species that attract bees and butterflies on its early spring blooms.
Golden Alexanders thrives in the wet prairie, and blooms bright yellow in the spring on one to two foot stems, but lacks drought tolerance so may benefit from some shade in a rain garden.
White wild indigo grows three to six feet, blooming white pea-like flowers, and the leaves can be a food source for skipper and some butterflies like the orange Sulphur.
Great blue lobelia prefers part shade because it is not fully drought tolerant, as it is native to wet prairies. It boasts blue flowers starting in the summer and into the fall.
Prairie drop seed is native prairie grass with dense tufts and sprawling leaves. The upright airy inflorescences are spectacular in the summer sun followed by seed heads with great winter interest to birds, but are also pleasing to the eye!