Preventing Runoff on Sloped Lawns

It’s never too early to think about Spring time. Usually, the freeze and thaw from snow and ice from the oncoming Fall and Winter months have an uncanny way of showing a property owner where trouble spots are in the yard. From settling to erosion areas to drainage issues, Fall and Winter reveals much. When Spring arrives so does the rain, and that rain can amplify the problem areas ten fold. If you do spot runoff issues, hopefully they are minimal. But fear not my friends, there are many ways to not only tackle the issues, but solve the problem that will help keep your yard in good shape.

If you have the money or the time you can grade as well as improve the tilt and texture of the slope of your lawn. Grading the slope into a gentle incline of 6 percent (6-inches per 100-foot of run) as well as include a well-drained topsoil should manage runoffs from all measures of rainfall except perhaps a torrential rain storm. Increase the topsoil by a layer of 6-inches over the final grade so the subsoil and topsoil share the slope. Add a lot of organic materials like rotted manure or compost to improve tilt and invite earthworms to colonize the area so that the soil under the turf can continue to be conditioned.

You can also improve the appearance of the area with permeable hardscapes like fieldstone patios and walkways. Use sand between the stones and to build terrace walls instead of mortar or cement. Add perennials around large rocks or wind gravel over subsoil drain tile gently across the slope to create a Zen-like stream that captures the water of the runoff.

Instead of turf for lawns you can plant perennial ground covers and ornamental plants that have the root system to hold the soil for years. This will serve you better than using annuals that have roots that die when the plant dies.

Lawns that feature slopes are susceptible to water runoff that can cause erosion and limit nutrients from getting to the roots of the grass. (Courtesy: Al Phoenix at

Lawns that feature slopes are susceptible to water runoff that can cause erosion and limit nutrients from getting to the roots of the grass.
(Courtesy: Al Phoenix at

If you find the need to seed a patch cover the seed with straw or mulch to protect it from being washed away so it has time to grow. De-thatch turf when the layer of dead grass collects to about 1-inch of thickness. This will prevent compaction of the soil and permit water to soak into the ground.

There are a large assortment of native plants you can use that bloom well on hillsides of lawns with very little maintenance. Native perennial grasses including alkali sacaton instead of invasive grasses like Pampas grass in areas that are especially susceptible to runoff. You can also utilize such native perennials as California aster and coneflower and western blue flag. Add organic mulch to protect the soil around the perennials and include stone or plastic landscape edging to retain the mulch and plantings.

One more alternative to turf and covers is to use xeriscaping plants. These florae and grasses are drought-resistant and form deep roots that will hold soil.

Another option to prevent runoff is to create plant beds on the hill. Since rainwater runoff moves down hill, it may be best to install plants that require a lot of water on the bottom of the hill and use plants that thrive better in more of a drought condition on the top. Such a layout will also allow you to include grass and will break up water flow that will limit erosion.

Inspect the slope for good locations for the beds and outline with spray paint to determine shapes and placement.

You will need to dig into and loosen the soil to prepare for the plants, and then you can go ahead and plant. If you decide on small plant beds, use plants like sun-thriving creeping zinnias and use some taller plants to provide a natural appearance.

Plants should be spaced to cover the entire bed. The look can be enhanced with the use of drought-resistant shrubs that can be located on the top of the slope. Good shrubs to consider for this includes purple rock rose (South and West regions of the U.S.). Groupings of plants within the bed can help to concentrate the eyes to particular spots along the slope. The bulk of space can be taken up with medium-size plants including silverbush (South and West regions). Use small flowers to fill in. Trees including flowering species like plum trees can be used to create height.

Refer to the USDA Plant Hardiness Zone Map to determine what florae will do best in your region of the country.

Dig a shallow trench and include rocks or pavers to serve as the edge for the plant beds. This will prevent mulch from washing down the hill and the trench assures that the stones won’t shift out of place. Stones can also be placed in the plant beds to help break up water flow and add texture to the location. Place the stones in a shallow hole in the soil to assure that they stay stable.

About Robert Janis

Written by Robert Janis for LawnEq - Your specialists for Lawn Mower Parts and Small Engine Parts. We offer genuine premium OEM parts for Land Pride, Toro and many more dependable manufacturers.