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.
3 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.
8 landscaping and styling solutions for plots on a hill
1. SURROUND A SEATING SPOT WITH LEVELLED BORDERS
Sloping garden ideas can be used to create show-stopping impact, as seen in this plot. The eye is drawn upwards by the wooden-cladded flowerbeds, which cocoon a verdant lawn. Curved steps add to the rustic feel.
Meanwhile, the seating space is given plenty of shelter, positioned on a decked area at the same level as the house. The result is a breathtaking view where all aspects of the garden can be appreciated at once.
2. BRIGHTEN THE SPACE WITH PALE WALLS
This tiered plot designed by Living Gardens(opens in new tab) demonstrates how sloping garden ideas can be used to create a modern, attractive space that all the family can enjoy.
There’s plenty of room to entertain on the hardwood deck. Above, a paved seating area is surrounded by a curved planter, which softens the design and provides soothing visual interest. A lush lawn takes up the lower level of the plot.
One of our favorite things about this scene, however, is the choice of materials and colors. The pale hues bounce light around, helping to open up the space and adding to the clean, elegant vibe. The resulting look feels airy and relaxed, and makes a wonderful backdrop to the verdant planting and dazzling agapanthus.
3. ADD A SOOTHING VIBE WITH CURVED FEATURES
Slopes don’t have to be flattened – they can provide character and opportunity for interesting design. This garden has a gentle slope, most of which was kept and turfed, explains Nigel Gomme, Landscape Designer of CITYSCAPERS(opens in new tab).
On one side, a series of tiered level beds cuts into the area. These step up in sync with the slope, with a stepped path snaking through them. We love the gentle curves, which are mirrored by the wooden bench. Together, they offer an organic, pleasing vibe.
‘On the other side of the lawn, we created a small stream that uses the natural fall in the land to meander down to a pond set into the patio by the house,’ Nigel says. ‘So in a single garden, the sloping topography of the site is expressed in three contrasting yet complementary ways and mostly, in fact, by keeping the slope.’
4. TRY A SERIES OF SMALL TERRACES
‘You can sometimes flatten a whole garden but you will often be left with a large height difference on one side or at the end,’ explains Jo Fenton of Fenton Roberts Garden Design(opens in new tab). ‘This will require a retaining wall which can be very costly and can introduce issues with overlooking your neighbors.’
Jo demonstrates an alternative approach to sloping garden ideas in this gorgeous plot. ‘In this garden we worked with the slope by designing a series of small terraces. The slope across the garden is dealt with by introducing two sets of raised beds where the clients grow their vegetables and herbs.’ It’s functional, stylish, and the shallow levels add visual interest to the garden.
5. PLANT BILLOWING BORDERS
‘Sloping sections of a garden can be hidden within the planted areas enabling other areas to be flattened for practical use,’ says Jo Fenton of Fenton Roberts Garden Design.
‘This steeply sloping garden was too extreme to flatten out entirely. Here, we mixed sloping flowerbeds with two paved terraces and a lawn. A narrow access path bisects this large planted area enabling the maintenance to be carried out.’
Adding plenty of height with textural plants adds a sense of romance and drama to the zone. This look would work perfectly as part of our cottage garden ideas.
6. ADD STATEMENT STEPS TO YOUR SLOPING GARDEN IDEAS
Whether you are linking terraces or adding definition to a steep slope, a set of practical and eye-catching steps will help define and add structure to the outside space.
A simple stairway built from blocks, timber sleepers or deckboards will of course do the job but can take up valuable floorspace. Instead, opt for some prefabricated metal steps – such as Corten steel designs – for your sloping garden ideas. Not only do they look rather chic and introduce a gravity-defying edge to any design, but they can hover over borders and have a minimal footprint too.
7. MIX SMART STEPS AND SLOPING BEDS
Graceful and easy on the eye – setting steps flush into a planted slope is not just practical but an elegant solution for sloping garden ideas. Solid and distinct, the secret is to make sure the size of each step is right for comfortably strolling up and down and that the width is generous enough to make a bold statement, especially when surrounded with lush planting.
Think carefully about choosing materials and the finished look. In this design, the dark hardwood steps echo the bold windows of the house but keep the look smart, yet organic too.
8. USE GABIONS AS A RETAINING WALL
Retaining walls are key to terracing sloping garden ideas and can become striking garden wall ideas too. There are plenty of options available and these vary widely in cost, planning and installation.
Blockwork walls – rendered or left bare – will require careful planning and preparation, as well as meticulously calculated drainage channels. Stone-filled gabions – such as these pictured – are a handy solution as not only are they strong enough to support hefty banks of soil, they look attractive and crucially let rainwater filter through.
Gabion sizes range from 0.5m to 2m wide baskets and can be made from rigid welded mesh or flexible woven wire.
