We have a hillside where we often walk that is becoming an eroded mud pile. How can we fix it?
One reason to get a cover crop in quickly is to prevent erosion, especially on slopes. During spring, when rain and meltwater are flowing, paths that run straight down a hillside are especially vulnerable.
Rerouting a path to travel back and forth across the slope, with switchbacks like an alpine road in a car commercial, can slow down water flow. Or, build stairs—they can ultimately have less impact on the landscape than a footpath. By corralling traffic to one, hardscaped route, you’ll protect the rest of the hillside. You can also redirect surface water with water bars so a path doesn’t become a sluice. The simplest water-bar design is just three rot-resistant 2x4s with their edges screwed together into a U-shaped eavestrough. Sink the bar into a trench that you’ve dug at an angle across the path and backfilled with crushed rock, with the open side at ground level. The bar channels water off the path, into the greenery on the side.
Christopher Willis, a contractor and the owner of JFW Construction in Port Hope, Ont., worked on erosion control along the Highway 407 extension, northeast of Toronto. Now, on cottage and residential renos, he sometimes uses scaled down mega-project techniques to address hillside erosion.
Among them is hydroseeding. Hydroseeding companies spray bare soil with a slurry of grass seed, mulch, and other additives—often moisture-retention agents, and a biodegradable blue-green dye the colour of a teenager’s hair statement. The dye fades quickly (it helps landscapers confirm that they’ve sprayed evenly), but the slurry holds and nourishes the seedlings so they can quickly establish themselves on the slope. “You could spray that stuff on asphalt,” says Willis, “and you’ll get grass.” (Though Willis says that Ministry of Environment rules preclude using it too close to waterways.) Over time, trees and other forest plants will establish themselves and outcompete the grass.
In spots where the erosion risk is high, though, Willis more often uses coir mats to stabilize the dirt and hold it in place. These coarse sheets are made of coconut husk fibres and are available in rolls from landscape supply companies. “They look sort of like brown wool fabric,” he says. All you have to do is lay them or similar products overtop a slope—plants will grow in and through the mat, which decomposes completely in a few years.
Plants that form thickets or spread by rooting aggressively can anchor hillside soil, says Kelly Leask, the owner of Prairie Originals, a native-plant nursery in Selkirk, Man. A vine that’s native to the area, she says, often works surprisingly well on a hillside. “Vines like Virginia creeper or Western virgin’s bower, if they don’t have something to climb, form adventitious roots along the stem, creating a ground cover.” Shrubs, such as willows and dogwoods, are also good erosion fighters. Be sure to find something that is native to your area. “Just take cuttings in spring, stick them in the ground, and they’ll root quickly,” says Leask.
This was originally published as part of “Back to Beautiful” an article in the Jun/July 2021 issue of Cottage Life.