Helen Newling Lawson is a freelance writer and extension volunteer. She offers deer-resistant gardening advice at DeerResistantDesigns.com.

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Gardening on a Slope
by Helen Newling Lawson       #Design   #Landscaping   #Slopes

Ground covers don’t have to be boring or just green. Snow ‘N Summer Asiatic jasmine sparkles along this stone pathway.
 

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, UGA professor Paul Pugliese advises you seek the advice of a professional. But many slopes can be managed with simple, inexpensive approaches.


Plants that naturalize, such as these daffodils (Narcissus spp.), increase in number every year and create a stunning sweep of color.


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.


A steep hillside alongside a driveway at this Atlanta home creates the perfect setting for a waterfall and pond. Boulders, ferns, and Hydrangea help stabilize the slope.


Handling overflow
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.

 


Top: This path helps control erosion and divides a formal terraced area from a more natural area.

Far Left: Millstones create a charming stairway to help visitors navigate a steep slope.

Left: For the ultimate low-maintenance solution to control erosion and improve soil texture, try this with storm-felled trees. In a technique called “sheet composting,” cut them down into shorter lengths and arrange them perpendicular to the slope, where they will slowly decompose in place.


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, UGA CAES recommends “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.”


Terracing with a series of stone walls breaks a steep slope into more manageable segments and bring flowers up to eye level. A drain in the flagstone terrace helps manage overflow.


Terracing
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.


Paths
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).
 

Southern Slopes
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

 

A version of this article appeared in a May 2018 print edition of State-by-State Gardening.
Photography courtesy of Helen Newling Lawson.

 

Posted: 04/30/18   RSS | Print

 

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