It is a challenge to landscape steep gardens, but it's also of importance. Without vegetation, steep hillsides experience erosion and landslides. However, well-planted hillsides are far less prone to either of these problems. The key is to disturb the existing soil as little as possible while providing the right mix of plants. When properly done, a steep garden is both beautiful and safer.
The Right Plants
The right plants offer steep hillside stability, according to Las Pilitas Nursery, which specialises in erosion control gardening. They recommend against choosing just one or two types of plants for a steep garden. Instead, the nursery suggests selecting a mix of ground covers, bushes and trees. The nursery's website advise against using annuals or perennials requiring frequent division, since this means disturbing the soil more frequently leading to erosion.
Gather ideas by seeking out steep areas where nature is still undisturbed. Determine what plants naturally grow on hillsides in your area. Adding those native plants to a steep garden will stabilise it. In addition, because the plants are native, it's unlikely anyone will need to disturb the hillside by tramping around it with a garden hose.
Lay 3 or 4 inches of mulch all around plants and in any bare areas to prevent water runoff and erosion. Avoid bark nuggets and other chunky mulches, as they tend to wash away when it rains. Instead, select shredded bark or other coarse mulches.
Gardeners must have access to steep gardens for weeding, watering and other maintenance. This means pathways are necessary. In especially steep areas, build steps into the pathway. Avoid covering pathways with gravel or any other loose covering, since these make it easier to slip.
Using some sort of dam to keep water from constantly rushing away from plants, recommends the Bonner County Master Gardener website. This could include using a stone or wood brace in front of plants, or creating a berm to grow plants on with a ditch or dam in front. Any of these methods will help prevent plants from drying out.
Adding several terraced gardens to a steep area makes gardening more manageable and prevents erosion on a hillside. However, disturb the soil as little as possible. Because landslides and erosion are such a concern, it is wise to hire an expert landscaper to create terraced areas on hillsides.
The Mississippi State University Extension website recommends against areas of grass on hillsides. Grass doesn't have a deep root system; therefore, it won't prevent land slides the way many other plants will. In addition, mowing grass on a steep hillside is a common cause of injury.