Upon moving in, Sam discovered that the low front yard would pool at the front of the house after a rain event. Seeing an opportunity within the challenge, she got to work on a solution to fit every season. She knew that she had heavy shade and space along the side of the house to work with, but also needed maintenance to be quick and convenient for long-term success.
Working with VLAWMO staff, a friend who’s an engineer, and another friend who is a landscape architect, the result was a raingarden combined with a newly graded swale. Runoff from the front of the house and part of the roof first gets stored and infiltrated into the raingarden basin, while overflow is sent to a gentle swale designed to escort water through to the back yard. While this was a great way to re-direct runoff in the summer months, it also helps save on winter maintenance and eliminates the need to use salt and de-icers.
But the heavy shade was still a puzzle, and the old oaks already demanded hours of leaf clean-up in the fall. Using an artistic yet practical approach, she realized that rock would support the use of a leaf blower, and could be designed into a Japanese Zen garden. For a final touch of innovation, Sam used native mosses blended with native shade plants to mimic what would typically grow under a dense oak canopy. While this was a new approach in VLAWMO’s cost-share grant program, Sam worked with staff to use the rock and moss while still meeting the grant’s native plant requirement.
Project size: 50 ft2
Drainage area into project: 1,106 ft2
Volume of water generated in project drainage area in a 1” rain event: 1,650gallons(~41 bathtubs)
Basin depth and overflow design: 8” (for sandy soil) Overflow directed to an extended backyard swale
Annual stormwater volume collected: 4,366 gallons/yr
Total phosphorus (TP) treated by raingarden: .011 lbs/yr
Total suspended solids (TSS) treated by raingarden: 2 lbs/yr
Native plants: Solomon’s Seal, Sensative Fern, Blue Flag Iris, Wild Geranium, Bleeding Heart, Turtlehead, Maidenhair and native mosses (Fern, Irish, Hedwigia, Tree Apron, Carpet).
Stormwater and treatment estimates provided by MPCA Minimal Impact Design Standards (MIDS).
What motives did you have to create the raingarden and where did you get the idea?
The entire yard slopes towards the front door and water would pool, which would become an ice-patch in the winter. I guttered the roof but then needed a place to put the water where it wouldn’t just flow back to the same spot. So the garden is solving a grading problem.
What strategies or needs went into the design process?
There are many large oak trees in my yard. I knew cleaning out all the leaves in the fall would be a problem. I wanted to be able to blow the leaves out of the garden with a blower, so mulch was not an option. I decided to try a Zen rock-garden style design with white rock (mimicking sand) in the bottom of the garden and moss around plants up the side slopes.
What do you enjoy most about the raingarden?
It has been fun to watch the plants come back in the Spring. And I’ve gotten a bunch a compliments on it, which is nice.
How has it changed your interaction with your yard?
When I moved in my yard only had oak trees and hostas. Now it has some flowering plants and ferns. The diversity is visually appealing and the garden creates a nice focal point, which was missing previously. Also, turns out kids like to use the grey accent rocks as stepping stones across the garden, so it is a little bit of a play thing too.
What’s the most challenging part of the raingarden?
I started with six different types of moss, but only two really took hold. (The mosses were not labeled when shipped, but I believe it was the Irish Moss and the Carpet Moss that were successful). Because the mosses were hard to establish, the side slopes were a little unstable the first year and I struggled to keep them from eroding into the bottom of the basin. Also, the plants were still small and not well-established in the first year. Because of that I was not able to use the blower as I had hoped. Now in the second year, the plants are a little bigger and the moss is more secure, so they’re more durable, and the low setting is working. Yay! The bottom of the rain garden does not require weeding; only the side slopes, but very little because the mosses do a good job of keeping most seeds from establishing.
What has surprised you as you’ve maintained the project?
The tall variegated irises in the bottom of the garden did not come back variegated. That’s a shame because they looked pretty cool the first year. Also, since it’s been such a dry summer, I tried a soaker hose connected to my rain barrel to water the garden, but there wasn’t enough pressure, so that didn’t work.
What would you do differently if you created another garden/native planting?
I’m not sure; I’m pretty happy with the results so far.