How to Stop a Washout on a Hillside Landscape

Sometimes the hillside of a yard develops problems with rainwater. If the hillside’s grass isn’t healthy or is exposed to lots of foot traffic, then over time it may develop washout places or ruts where the soil erodes. Avoid that from occurring, or prevent it from getting worse, by arranging landscaping plants to split the rainwater’s path.

Plant several trees around the hillside, spacing them to account for the spread of their limbs as they mature. The trees will pull in some of the rainwater that lands around the hillside and redirect other rainwater in different directions. A variety of trees may add firmness, including tulip tree magnolias (Magnolia x soulangeana), which prefer partial sunlight and grow in U.S. Department of Agriculture (USDA) plant hardiness zones 4 through 9, and flowering plum trees (Prunus cerasifera), which enjoy full sunlight and grow well in USDA zones 8 through 10.

Set rocks along the hillside to reroute rainwater and also to split it into smaller, less damaging streams. Dig out some of the hillside’s soil so the stones can place without the potential for rolling. Place several medium-size stones, 12 to 24 inches in diameter, in groups to make their look natural, or form a small rock garden. Using rocks bigger than 24 inches in diameter can also be powerful, but these stones are a bit too difficult to maneuver up a hill without help or equipment.

Place small plants, such as rose impatiens (Impatiens walleriana), and ornamental grasses, such as mondo grass (Ophiopogon japonicus), between the stones to fill the spaces and make the landscape look natural, like the stones were there all along. The plants will hold dirt in place also, raising your chances of preventing additional washout. Rose impatiens function well in USDA zones 4 to 10 and prefer shady locations. Mondo grass does best in a sunny place in USDA zones 6 through 8.

Dig out dirt to create ledges if the washout is a significant issue and the hillside is too steep that you often trees and plants. Scoop the soil out to form flat surfaces or tiers, and contain the fronts of the tiers with landscape timbers or large rocks. Add trees and plants on the respective ledges, making a fully landscaped space. The rainwater will fall upon the flat surfaces and also be drawn more readily into the dirt than it would on a hillside without ledges. Plant examples for your ledges consist of sun-loving creeping zinnias (Sanvatalia procumbens), which can be annuals that grow well in most of USDA zones, ornamental grasses, such as mondo grass, and also Angel’s trumpet (Brugmansia), which prefers partial sun and grows best in USDA zones 9 through 11. Flowering plums are among trees that can be implanted on the hillside ledges.

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