How to Garden on a Slope: 12 Ideas for Hillsides

Terracing a Hillside Vegetable Garden

A hillside can be a blessing when designing a vegetable garden, especially a south-facing slope. This west coast garden shared by the Pacific Horticulture Society takes advantage of the elevated ground along the trellised side by planting flowers that will be at eye level as someone walks down the path. Each terraced row is on its own level and gets direct sunlight without being shaded by the row in front. It can be a challenge to get supplies and water to the area. It would be wise to consider drip irrigation, and pathways between the vegetable rows are a must.

Anchoring a Hillside Garden

The soil on a hillside is often less than ideal. The topsoil tends to wash off quickly, taking the nutrients and fertility with it. It's not uncommon to have a hillside, primarily rocks, barely covered with a topping of soil. In that case, you may have to create planting pockets and add some additional soil to establish plants.

This gardener made use of two workhorses, astilbe and hosta. Both can grow in the shade of this creek hillside, and both are hardy enough to take hold in the poor soil. She divided the original plants and quickly covered the entire slope within a few years.

Terracing a Hillside With Stone

Stone walls are a classic way to terrace and tame a hillside. Although they are a lot of work initially, once they are in place, you have a functional and attractive structure. Stone walls can create planting areas wide enough to work in and around, and they even look good on their own, requiring very little fanfare from the plants contained in them. Since stone tends to heat up early in the spring and hold heat at night, you are creating a microclimate that will allow you to grow plants that would not survive in other areas of your yard.

A Borrowed Hillside View

A hillside can become part of your landscape even if it tapers off into the distance. These homeowners live near a wooded lot that slopes toward their yard and house. They limbed up the trees to create a clearer view. They underplanted with actual woodland plants such as maidenhair ferns (Adiantum) and mayapples, as well as rugged workhorses like hostas and foamflower (Tiarella). The effect is almost a fairytale setting that sets the house as a destination.

Taming a Hillside in Small Bites

When the angle of the slope is extreme, stairs are a necessity. However, you do not have to landscape the entire hillside—at least not all at once. Take advantage of the area closest to your living area and create manageable planting boxes. At the lower levels, you can do it without extra equipment, and the boxes are not just easy to work in; they create a garden room for relaxing and entertaining.

A Natural Hillside Rock Garden

Part of the challenge of landscaping a hillside is establishing the plants before they wash down the slope. Plants need water to become established, and watering a barren slope is an invitation for runoff. If you are not going to be terracing the hillside and creating flat areas for planting, adding large rocks and boulders is a good alternative way to anchor the soil while the plants take hold.

This gardener made his hillside rock garden look natural by allowing the rocks to tumble and land where they may. Some weeding and maintenance are involved in the early years, but it becomes less as the plants spread out. As the plants fill in, it looks like the whole garden evolved independently.

Gardening a Roadside Slope

It's lovely to have a house situated on a hill overlooking the landscape, but that sometimes means your yard slopes down to the road, giving you the effect of a hell strip in your front yard. As with any other slope, you need tough plants that won't require a lot of grooming. Shrubs and evergreen are ideal for this situation. Since you don't want to obscure the view at the side of the road completely, fill in the front section with lower-growing perennials that will not need frequent division, such as hosta and ferns. 

Creating an Alpine Hillside Garden

Consider yourself lucky if your hillside is basically scree or naturally covered in rocks. You can create a unique alpine garden that will draw the eye upward. Follow this gardener's lead and use the existing rocks, but reposition them. Larger slabs are used as steps and platforms. She also makes liberal use of hypertufa or artificial limestone, which blends in beautifully with the natural stone. Finally, pea gravel is used as a mulch, to prevent runoff and create a unifying color palette.

Large evergreens give the planting weight, and self-sowing perennials, like corydalis, are allowed to fill in where they will and soften the rocky ledge.

Turning a Hillside Into a Garden Walk

Terracing the walkway while leaving the planting area elevated gives the effect of encompassing passersby in the flowers. Instead of steps, these homeowners have chosen to lay stepping stones with just enough traction to keep walkers steady.

The exuberant perennials along the walkway are given even more level changes by using containers and pot stands on the lower levels, which create focal points for the journey down. And drivers passing by on the road get a full view of the hillside garden, rather than only the front few plants a flat garden would afford them.

A Four-Season Hillside Garden

When you have a hillside that frames a view of your house, you want it to remain attractive year-round. Colorful shrubs are the perfect answer. Not only do they have four seasons of interest, they require minimal, if any, maintenance. A little pruning in the spring and your hillside should look good for the rest of the year. And shrubs are excellent for controlling erosion. Summersweet (Clethra alnifolia), California lilac (Ceanothus), and prostrate rosemary make good choices.

Covering Ground on a Hillside

For a gentle slope or berm that connects a wooded area with your open lawn, create a smooth transition with groundcovers that naturalize and create a colorful carpet. The soil will drain quickly on a berm, so treat it like a rock garden and use plants such as creeping phlox, alpines, perennial geraniums, and tiny bellflowers. Using flowers in white and soft pastels will keep the cool feel of the woodland. You can extend the color past the spring bloomers with white and yellow variegated foliage.

Low-Maintenance Plants for a Hillside Garden

Runoff is one of the biggest challenges with hillside gardens and even more so when the slope runs off into the driveway, where soil can settle. Choose plants that will anchor the hillside, such as shrubs, ornamental grasses, and prairie plants, like coneflower, that form a mat of roots. All these plants hold the ground in place and require minimal maintenance during the growing season. They can even be left standing for winter interest.

With a bit of thought when choosing your plants, any hillside or slope can become a focal point in your yard.