My rain ditch garden
After learning about rain gardens through Wild Ones, I wanted to put one in our yard. The problem was I could not put the rain garden in the typical placebeside the house where the downspouts drain. Even now, during wet springs, water seeps into our basement. Because of saturated soil, our downspouts drain through underground pipes to the ditch in front of the yard, along a public road. I realized this ditch presented me with the perfect opportunity. By planting natives there and up the steep slopes, I would solve several problems at once, and I would get my rain garden.
Because this area of my yard is right next to the road, I have always tried to make it look tended, and this has been a bother. The uppermost area dries out and wont support grass; the bottom of the ditch is soggy well into summer; and in between, the slope is too steep to mow. As a bonus, a native planting in this area would slow down rain water surges and let the water infiltrate into the soil.
Rain garden benefits
Reduce rain-water runoff that would end up in waterways, causing flooding
Reduce pollutants that typically are carried off in rain water
Slow runoff, giving it time to infiltrate into the earth
Facilitate water infiltration with the extensive roots of native plants
Provide a natural habitat for wildlife, including birds, butterflies and bees
Enhance the yards beauty
Installing the rain garden
Before breaking ground, I called the township road commissioner. Since the township controls the easement, I asked if I could plant in the ditch. I explained that I wanted to plant a rain garden with native plants (hoping to pique his curiosity enough to drive by to see what it is about). He had no problem with what I described.
The project started in 2004, and I expected it would take at least six years to complete it. To organize my thinking and determine what plants I needed and where they should go, I took measurements and drew a diagram. Plants were grouped by height and soil moisture requirements. The diagram helped me visualize how it might look to passers-by.
To prepare the site, I sprayed Round Up® to kill the turf grass and weeds. I did not rototill the site because I did not want to bring up weed seeds. After the grass was dead, I mulched with shredded leaves and started planting the plugs of natives directly into the dead turf. Later, I added horticultural annuals into the spaces between the natives. This temporary measure filled in the garden while providing color for the first year. I knew the natives would put most of their energy into building roots, their first year of growth. The horticultural annuals would die at the end of the season, and would not re-seed themselves.
To give the planting an organized look, the border is lined with prairie dropseed (Sporobolus heterolepis), bebbs sedge (Carex Bebbii), native petunia (Ruellia humilis) and prairie smoke (Geum triflorum). They established nicely, but, by the second year (2005), I realized I needed to add to my groupings of species so they would be showier. To slow the water down, I built a series of small dams made of soil and leftover landscaping stones. Now, following a rain, water pools up 4 to 6 inches deep, but disappears within a day.
Last fall (2006), I added a small rain garden at the top of the slope to collect water from one of the downspouts on the garage. I dug this one with a rototiller and by hand, so it has a fairly level bottom and is about 6 to 8 inches deep. I used the excess soil to create a berm on one side.
My need to add this upper garden was entirely of my own creation: I bought a red elderberry (Sambucus pubens), which likes moist soil and part shade, and I had no other place to put it. A nearby maple will benefit from the moist soil and provides shade for the elderberry. Furthermore, this little garden retains its own complement of rain water, and any excess flows down into the lower rain garden.
In their third summer after planting, the 2004 sections of this project were spectacular and drew a lot of butterflies and bees. Neighbors walking by stopped to look at it and complimented its beauty. With this success, I was motivated to add more to it last fall (2006), along with the upper elderberry garden. My plan is to continue adding to this garden over the next few years until it abuts my neighbors property. Just imagine if everyone in my neighborhood were to put in rain gardens in the storm water ditches. Very little water would reach the subdivisions detention area.
Tim Lewis is immediate past president and national director of Wild Ones.
from the April 4-10, 2007, issue