Is your landscape going downhill? These landscaping ideas will transform your steep drop-offs and slippery slopes into beautiful, functional centerpieces in your yard.
Finding your slope’s steepness
Before you redesign your landscaping, your first step is determining the steepness of your slope so you know which landscaping options are right for you. The easiest way to do this is the stake method.
What you need:
- Between 2 and 10 stakes (the steeper the slope, the more stakes you’ll need)
- A line level
- String
- A pen
How to check the grade of your slope with stakes
If your slope is mild, you might only need two stakes. If it’s steep, you’ll either need very tall stakes or one to plant every few feet.
1. At the lowest point of the slope, insert one stake a few inches into the ground.
- For a steep slope, insert the next stake 2 feet from the first, going up the slope. Continue to add a stake every 2 feet until you reach the top of the slope.
- If you have a mild slope, insert the second stake at the top.
2. Tie a string to the bottom of the stake (where it meets the ground) at the higher elevation.
3. Using a line level attached to the string to make sure it’s straight, mark where the string meets the stake planted at the lowest elevation.
4. Measure the distance in feet between your mark and the ground. This is the change in elevation between the two stakes.
5. Divide the change in elevation by the distance between the two stakes and multiply this number by 100 to find out the percent slope (or grade change).
- Example: The vertical distance between the ground and where the string meets the stake at the lower point is 2.5 feet. The horizontal distance between the stakes is 5 feet.
2.5 feet ÷ 5 feet = 0.5 feet
0.5 feet ×100 = 50
The grade change is 50%. This means that for every one foot of horizontal distance, your area declines or rises by half a foot.
If you have more than 2 stakes, perform this calculation between each one, then add all the percentages together and divide by the number of areas measured to find the average.
Landscaping solutions for your slope grade
If your slope’s steepness is less than 33%, runoff can be controlled with plant materials, mulch, pine needles, and rocks.
If your slope is between 33% and 50%, you’ll probably need the additional security of landscape fabric like mats, jute netting, and erosion control blankets beneath organic materials.
If your slope is over 50%, you need special structures like stone and wood retaining walls, riprap (rock areas), or terraces.
Things to know before deciding on your slope design
There are a few aspects of your yard to check before choosing what slope design is right for you.
What type of soil do you have?
Sand is more prone to water erosion than clay. Poor silt soils are at high risk for erosion. If you have one of these types, choose a more secure option like a retaining wall.
What water requirements will your plants have?
To minimize water waste, use hydrozoning. Group plants together based on water requirements. Plants that need more water should be planted toward the bottom of the slope.
How much sun or shade does your slope get?
Some plants and grass need plenty of sun. Well-shaded areas could benefit from stone structures instead.
5 ideas for landscaping on a slope
1. Anchor plants
A great way to spruce up the look of your slope and control erosion is with plantings. Ground covers and shrubs are especially effective at increasing the quality and quantity of soil on a slope.
The root system of a vigorous, well-established plant can hold soil in place on a hill. The foliage can also slow down heavy rain. In addition, the plants give nitrogen back to the earth, resulting in a more nutrient-dense topsoil.
We prefer native plants because of their low maintenance needs and pollinator-friendly qualities.
Native ground covers
- Deer fern
- Redwood sorrel
- Bunchberry dogwood
- Wild ginger
Native shrubs
- Spirea
- Mock orange
- California lilac
- Elderberry
Native trees
- Willow tree
- Showy mountain ash
- Red twig dogwood
2. Mulch
Mulch is the humble hero of landscaping. It adds a beautiful pop of color to your slope, especially as a border for trees and shrubs. It prevents weeds, pests, and protects topsoil from being blown or washed away.
Mulching is our lowest maintenance option, and it’s an easy DIY. All you need are a few bags of mulch (or your own compost) and a free afternoon. For a seamless look, feel free to stick with a plain layer of mulch. For more visual interest, incorporate mulch into any of the other landscaping ideas here. It can provide a base for shrubs, accent a terraced flower bed, or accompany a rock garden.
To find out how much mulch you need, figure out the square footage of your slope. Multiply the width by the length of the area, then multiply that by the depth of mulch you want (a good rule of thumb is a 2-inch layer of mulch, but you’ll need to convert inches to feet before multiplying). Mulch is sold by the cubic yard, which covers an inch-deep layer over a 324-square foot area, so divide the total by 324.
Example: If the area is 12 feet wide and 17 feet long, you would multiply 12 by 17 to get 204 square feet. This is the area in square feet.
- For a 2-inch deep layer, you’ll first need to convert inches to feet: Divide 2 by 12 to get 0.17 feet. You want your mulch area to be 0.17 feet deep.
- Multiple 204 square feet by 0.17 feet to get 34.68 cubic feet. Then divide by 27 to get 1.28 cubic yards. You would need 1.28 cubic yards of mulch to give your slope a 2-inch layer.
3. Touch it up with turfgrass
Who doesn’t love a rolling green hill? Turfgrass is an awesome option for a clean, green look.
If you have a mild slope, turfgrass alone is fine. If the percent slope is greater than 33%, though, you’ll want to put down some kind of erosion-control blanket first. The last thing you want is erosion creating bald patches in your once beautiful grass.
What kind of grass should you choose? Take a look at our chart to see whether your climate calls for warm-season or cool-season grass.
| Grass type | Sun needs | Care |
| Bahia | Full sun to part sun | Low |
| Bermuda | Full sun | High |
| Centipede | Full sun to part shade | Low |
| Zoysia | Full sun to part shade | Medium |
| St. Augustine | Full sun to part sun | Medium |
| Kentucky bluegrass | Full sun to part sun | High |
| Fescue | Full sun to part shade | Low |
| Bentgrass | Full sun to part sun | High |
| Ryegrass | Full sun to part shade | Medium |
4. Rock it out
Rocks are a gardener’s best friend. Rocks used for erosion control on a slope are called riprap. That just means a permanent layer of boulders and stones that protect the soil surface from water runoff.
Rocks don’t have to be boring. There are lots of different aesthetic options, from earth-toned pea gravel to smooth river rocks to boulders that make a statement. Spend some time measuring your area to see what kinds of configurations make sense.
For effective erosion control on a steep slope, choose angular stones instead of smooth ones. The jagged edges knit together, so they’re less likely to wash away. They should be less than one-third as wide as they are long.
Rock combinations:
- Pea gravel or cobblestone with native plants to create a rock garden
- Stacked flat rocks to build a stone retaining wall at the bottom of the slope
- Anchor plants with flat boulders to mimic step terracing
5. Step terracing
How does descending down a beautiful garden path sound? Step terracing is the perfect option for a steep slope. Essentially, you add several retaining walls to a hill and flatten the areas between them. It breaks the hill up into plateaus to stop runoff and provides a great base for several landscaping options.
Terracing isn’t always a beginner-friendly project. To do it yourself, you’ll need time to plan and check building codes. Depending on what kind of step terracing you’re building, you’ll also need tools like a level, shovel, sledgehammer, pickaxe or digger, and drill.
Options for step terracing materials:
- Logs
- Concrete blocks
- Bricks
- Stone
Once you have your terraces, you can get creative with how you’d like to fill them. Anchor plants will increase the erosion control power of your terraces. You can also place flower boxes or vegetable gardens on each plateau.
All about erosion on slopes
What is erosion?
Erosion is the wearing down of the Earth’s surface by wind, water, and ice. Topsoil, the layer of earth closest to the surface, is the most susceptible and also happens to contain the most nutrients for your plants. Slopes are much more likely to experience erosion because of water runoff and the increased force of gravity.
The two major problems associated with erosion? Decrease in soil quality (also called degradation) and decrease in soil quantity (also called soil loss). Too much sun on a hill will cause evaporation, lowering soil quality by carrying away nutrients. Consistent heavy rainfall on a slope often causes a loss of soil particles.
Effects of erosion:
- Patchy lawns
- Weak plants susceptible to pests
- Destabilized driveways
- Clogged neighborhood drainage
- Harm to aquatic life and air quality
- Harm to your home’s foundation
How do you stop it?
Our slope landscaping suggestions aren’t just for aesthetics; they’ll also defend against erosion. There are two main approaches to preventing erosion: Stabilizing the soil with plant roots and netting or creating artificial plateaus or walls with something like terracing to slow down runoff. They can be used separately or together for additional security.
Making the most out of your landscaping
The design plan is just the start to turning your slope from a drag to a star feature of your landscape. These resources will help you get started on installation and make the most of your vision so it continues to thrive.
- How to plant grass seed
- Lawn mowing tips and tricks
- Ground cover tips
- How to install landscape fabric
- How to use landscape fabric in a garden or flower bed
If you don’t have time to DIY, contact a professional landscaping company in your area. They’ll take care of the design, installation, and maintenance.
Main Photo Credit: Shutterstock
