If your property has a large slope of 15% or more, you may want to consider growing turfgrass on your lawn to prevent erosion. However, sowing turfgrass may not be the simplest or best option.
Not only is it difficult to hold grass seed in situ long enough for it to germinate, but most tuft grasses are shallow-rooted and hence not well suited to the tough circumstances that a slope may bring.
Furthermore, lawn mower manufacturers caution that mowing on a hill is difficult and might potentially harm your mower (if it lacks an oil pump, the oil may not flow correctly during a lengthy hillside session, which can kill the engine).
All that considered, you’re not completely out of luck—while traditional turfgrass may not be the ideal option for your property, there are several grasses that can thrive in that exact area.
The ideal grass for your site can differ based on where you live. Buffalo grass is a suitable option for property in a dry, warm location of the United States. The plant has extensive roots, grows slowly, needs less mowing than other grasses, and tolerates drought well.
For northern areas with more rain and cooler weather, consider a mixture that boasts a significant amount of creeping red fescue. It makes for a great shade grass, and is equally as attractive mowed and unmowed.
Deep-rooted “bunching” grasses function well on slopes as well. Bluestem, prairie dropseed, sideoats grama, orchardgrass, and Indiangrass are some of the best non-turf grasses.
When considering how to plant your hillside grass, there are several methods that could work—the best depends entirely on your specific landscape and situation.
Simply mix the seed into the soil if you’re spreading seed onto a recently prepared location with loose topsoil. Though this may need extra seed, combining the two increases the likelihood that there will be seed even after some erosion. After sowing, cover the mound with straw.
A slice seeder may be appropriate if the slope of your landscape is less than 25%. The instrument, which resembles half a push mower, cuts small incisions in the ground and deposits the seed straight into the soil, rather than on the surface. This may assist the grass roots establish themselves stronger and deeper into the soil, increasing the likelihood that they will survive harsh or unusual weather.
“Blanket seeding,” which attaches seeds to the ground using “blankets” produced from different natural or biodegradable materials such as curlex or coir, might benefit particularly tough settings. This keeps the seeds in situ long enough for them to germinate and develop without being disturbed.
Live Plant Options
When in doubt, sometimes live plants are the best way to green up a hillside. Varietals like bermudagrass, centipedegrass, or zoysiagrass are all frequently started from sprigs, a method in which live roots are distributed into the soil using a rake. They have a higher success rate than seed on difficult sites since the plant is already alive. Keep in mind, it can take about six months to one year to achieve coverage with sprigs, however.
Likewise, grass “plugs,” also a common method, are small plants usually grown in trays of 36 to 72 units with five-inch deep roots. When planted into the hillside, grass plugs have a success rate that is usually much higher than with surface seeding—though the expense is greater as well. In northern climates, deep-rooted warm-season and cool-season grasses are often installed on hillsides from plugs.
Finally, remember that turf grasses and grass plantings are simply one option for covering a steep slope. Nature would have naturally covered such steep regions with trees, bushes, or other plants in the past. As an alternative to a grass-covered landing, consider a mixed planting of native trees or shrubs.
Terracing With Retaining Walls
Although it is a lot of effort, extensive landscape modification will make long-term management of a hillside property much simpler. Installing one or more retaining walls along the slope of your property may help you turn a long, steep hill into a series of plateaus where you can plant small patches of flat, easy-to-care-for grass. If they are big enough, these flat surfaces may also be used for recreational purposes (such as a patio or lawn swing), or they can be turned into food or flower gardens.