Growing Grass on Slopes and Hillsides

  • 01 of 04

    Is Turfgrass the Best Choice for a Hillside Ground Cover?

    Mowing grass uphill can be hard work.
    Mowing grass uphill can be hard work. Marsi, Getty Images

    Got slopes? It may seem as though grass is the least expensive way to cover soil on hillsides. Or perhaps grass looks like the best way to stop erosion.  

    But turf may not be the best choice. Consider these points:

    1. It's difficult to keep seed in place long enough for successful germination. (See the next step for an outline of growing techniques and seeding options.)
    2. Most turf grasses are shallow-rooted and not well adapted for challenging slope conditions. (Yes, there are a few exceptions. See section 2 of this step-by-step.)
    3. Hillside mowing is difficult. ​​Mowing accidents occur on slopes, especially inclines over 15 percent.
    4. If your mower doesn't have an oil pump, oil may not circulate properly during extended hillside operation. The lack of oil can ruin the engine. 
    5. If you live in a fire-prone area, hillside grasses may pose a hazard. It can be hard to extinguish flames on steep areas. Fire-resistant shrubs and trees may be a better choice.

    If you plan to use grass, however, see the next panel for species selection and planting techniques. 

    Continue to 2 of 4 below.
  • 02 of 04

    Grass Selection and Planting Techniques for Hillsides

    Man sowing grass seed on steep hill.
    Steep hillsides can be difficult to seed with grass. Kathleen Groll Connolly

    First, select the best lawn grasses for hillsides in your planting area. 

    If the site is in the dry, warm areas of the U.S., buffalograss (Buchloe dactyloides) is a good choice. The species has long roots, grows relatively slowly, requires less mowing than most grasses, and is drought tolerant. 

    For northern areas with more rain and cooler weather, consider a mix with a significant amount of creeping red fescue (Festuca rubra). This fescue is also good shade grass.  

    Deep-rooted "bunching" grasses work well on hillsides. Some top choices among these non-turf grasses include little blue stem (Schizachyrium scoparium), prairie drop seed (Sporobolus heterolepis), sideoats grama (Bouteloua curtipendula), blue grama, (Bouteloua gracilis), wavy hairgrass (Deschampsia flexuosa), and Indiangrass, (Sorghastrum nutans).

    When considering how to plant, see which of these five ways is best for your situation:

    • If broadcasting seed into a newly prepared site with loose topsoil, mix the seed into the soil. Though this may require additional seed, mixing improves the chances that, even after some erosion, there will still be seed. Cover the hill with straw after seeding. 
    • If the grade is less than 25 percent, a slice seeder may work. This equipment makes tiny slits in the earth and places the seed directly into the soil, not on the surface.
    • Consider hydroseeding, the practice of mixing the seed with a mulch slurry that adheres to the surface long enough to facilitate successful germination. (This is also called hydraulic mulch seeding, hydro-mulching, or hydraseeding.)
    • Look into "blanket seeding," securing seed with "blankets" made of various natural or biodegradable materials. Curlex blankets, for instance, hold the seed in place. Coir (shredded coconut) blankets do the same.

    For a more reliable method of planting hillsides, turn to the next panel for some ideas on landscape plugs.  

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  • 03 of 04

    Install Grass Plugs or Sprigs to Create a Grassy Hillside

    St. Augustinegrass
    St. Augustinegrass is almost always established from plugs, a good technique for planting a hillside lawn. Wikimedia Commons

    Sometimes live plants are the best way to green up a hillside. 

    Bermudagrass, centipedegrass and zoysiagrass are frequently started from sprigs or plugs. St. Augustinegrass is almost always installed that way. (These are all for southern lawns.) 

    Grass "sprigs" are live roots that can be distributed into the soil with a rake. These have a higher success rate than seed on difficult sites since the plant is already alive. It can take about six months to one year to achieve coverage with sprigs, however. 

    Grass "plugs" are small plants, usually grown in trays of 36 - 72 units, with five-inch deep roots. When grass plugs are planted into the hillside, the success rate is usually much higher than with surface seeding. The expense is greater as well. 

    In northern climates, deep-rooted warm season and cool season grasses are often installed on hillsides from plugs. See New England Wetland Plants or North Creek Nurseries for examples of grasses adapted to northern climates. 

    Continue to 4 of 4 below.
  • 04 of 04

    Revegetate a Hillside With Shrubs, Trees and Perennials

    Hillside in flower.
    There are many wonderful choices for covering hillsides. Kathleen Groll Connolly

    Finally, keep in mind that turfgrasses are only one way to cover a steep hillside. Historically, nature would have covered steep areas with native trees, shrubs, or other plants. Relatively few grasses are adapted to hillsides. Consider a mixed planting.