From plants to pathways … easy ways to handle a tough site
Story and Photos by Helen Newling Lawson
Many landscapes have at least some degree of slope. In certain situations, a slope can be a design asset, allowing you to create interesting features or place certain garden elements at eye level. But steep slopes can create mobility or erosion issues that sometimes require some type of landscaping solution. For walls higher than approximately 1 foot, professor Paul Pugliese advises you seek the advice of a professional. But many slopes can be managed with simple, inexpensive approaches.
Using Slopes to Your Advantage
Love the look of a rock garden? A slope can help make placed boulders look more natural, as if they have emerged through the hillside from natural erosion rather than by design. To get this effect, bury at least one-third of the rock below ground.
A hill can also make a stream or waterfall look like a natural occurrence. Whether you create a dry streambed to direct runoff during rains or install a pump to have a constant flow of water, a tumbling stream doesn’t make sense without a slope.
Installing a rain garden is an attractive and environmentally friendly way to collect runoff from a slope. Not only is a properly designed and planted rain garden a low-maintenance “self-watering” addition to your landscape, rain gardens also limit pollutants from reaching our waterways.
What to Plant
The right plants can be useful allies in the battle to conquer your hill. Ground covers are usually the go-to choice. But plants with fibrous roots, such as goldenrod, or those that spread by suckers or self-rooting, such as sweetspire (Itea) and Forsythia, can add interest with varied heights. Low-maintenance, mat-forming plants like sedges (Carex spp.) also work well. Pay attention to the changing moisture conditions along the slope, and pick plants suited to these microclimates. See the sidebar for some top choices for Southern gardens.
If you plan to use plants to control your slope, mulch is essential. It will help hold soil and control weeds while their roots establish. For steep slopes, use either pine straw or finely shredded wood mulches, which tend to stay in place better than other types. Wood chips and pine bark nuggets tend to float away with heavy rains.
If you still think your site requires a retaining wall but want to tackle it yourself, try installing a series of terraces to keep the height of each wall to a manageable 12 inches. Dry stack construction might be a good option – the lack of mortar can mean better water drainage between levels.
Building steps may be the most straightforward way to navigate a slope, but an indirect route can be more cost effective and pleasurable. Try creating a zigzagging path perpendicular to the slope using a series of gentle switchbacks. Although it will take more steps, it will also require less effort and will offer an opportunity to enjoy a leisurely stroll through the garden – especially if you border the path with fragrant ground covers, such as Gardenia ‘Prostrata’ or sweetbox (Sarcococca hookeriana var. humilis).
Here’s a short list of great plant choices to try if you’re dealing with a tough slope
Goldenrod (Solidago spp.) – Fibrous roots on these native pollinator-friendly plants turn a hillside gold in fall. And no, you aren’t allergic to it – blame ragweed, which blooms at the same time.
Snow ‘N Summer Asiatic jasmine (Trachelospermum asiaticum ‘HOSNS’) – A moderate growth rate paired with showy pink and white splashed new growth and fragrant white blooms makes this an elegant addition to a high-visibility hill.
Inkberry holly (Ilex glabra) – A native shrub with suckering stems to fill in hillsides and wildlife-friendly berries.
‘Max Freii’ soapwort (Saponaria x lempergii ‘Max Frei’) – A tough site still deserves flowers. This mat-forming selection holds up to heat and humidity, and is deer-resistant, too.
Allegheny spurge (Pachysandra procumbens) – The native cousin of Japanese spurge is worth seeking out for a shady site.
Creeping raspberry (Rubus hayata-koidzumii, syn. R. calycinoides) – Attractive scallop-shaped leaves on a shade-tolerant ground cover.
Creeping thyme (Thymus spp.) – A fragrant choice for edging or to drape over a retaining wall.
Sedges (Carex spp.) – A wide variety of grass-like plants, many of which tolerate shade or drought.