Suitable plants, decent well-draining soil, and proper irrigation combined in a well thought-out and appropriate design solved maintenance difficulties at a busy northwest-facing intersection in Roanoke, VA. Soil in Roanoke, located in the state's Valley and Ridge physiographic province, is rolling and composed of mixed varieties in most landscaping projects. Readers seeking a wintertime, all-inclusive view of this site when newly planted can access it by typing in the road intersection, Brandon Rd. and Deyerle Rd, Roanoke, VA, 24018 at Google maps and open the traffic photograph for a plane view. Planting and completion of the slope took place in 2006.
Simple Slope Design
The design divides the slope into ten sections and specifies plants that are useful as out-of-the-ordinary ground covers for each. Foliage colors as well as blossom colors for the listed plants harmonize to provide unity to the design.
Three sections use these evergreen shrubs:
- 'Soft Touch' Japanese holly (Ilex crenata 'Soft Touch'), mature height 3-4 feet;
- 'Harbor Dwarf' Nandina (Nandina domestica 'Harbor Dwarf'), mature height 2-3 feet; and
- 'Rheingold' arborvitae (Thuja occidentalis 'Rheingold'), mature height 3-5 feet.
Six sections use basic perennials, most of which are native to North America:
- perennial sunflower (Helianthus decapetalus 'Plenus');
- purple coneflower (Echinacea purpurea);
- Shasta daisy (Leucanthemum species: x superbum and synonyms: Chrysanthemum x superbum and Chrysanthemum maximum);
- 'Moonbeam' threadleaf coreopsis (Coreopsis verticillata 'Moonbeam'); and
- goldsturm coneflower (Rudbeckia fulgida 'Goldsturm').
In addition, one section uses an ornamental grass:
- Maiden grass (Miscanthus sinensis).
All plants were transplanted perpendicular to the slope into small level areas constructed around each plant. To reduce runoff from rain and irrigation, plants were set into zigzag rows, like a checkerboard.
Robust turf grows at the bottom of the slope between the plantings and roadway. Three medium-size crape myrtles (Lagerstroemia indica ) divide this space.
Maintenance Advantages of and Concerns with this Design
Typically, mowing and weeding are the biggest problems in slope maintenance. Although regular seasonal mowing is still necessary, planting turf on the site's flat portion decreases characteristic difficulties.
Landscape fabric and fine bark mulch covered newly planted beds. Currently, reliable landscape maintenance that includes spreading a thin layer of protective and decorative fine bark mulch each spring keeps weeding to a minimum.
Even though selected plants are comparatively drought-tolerant, regular irrigation during southwest Virginia summers is beneficial and would be valuable in other plant hardiness zones. All the plants including the perennials and ornamental grass mature at relatively small sizes.
Absence of walkways eliminates structured pedestrian access and litter except for some windblown debrus from the road. Grade of the slope plus no clearly defined objectives like a bus stop or neighborhood store deter unstructured pathways through plants.
Deadheading the perennials would probably nurture a second but less showy flowering cycle, but labor limits this chore. After five years of growth, the perennials need to be divided and replanted, and overall numbers increased to fill gaps left from some seasonal failures.
Periodic weeding, cutting back perennials in the autumn and some pruning of the three evergreen shrubs and crape myrtle trees along with spreading mulch are the only serious annual maintenance tasks required.
Key Factors Make This Design Successful
Soil suitable for plant growth, a practicable automatic or manual irrigation system, and plants to match site requirements were the beginnings of successful execution for this slope design. Barbara Ellis' Suite101 article "Landscaping Slopes in Full Sun: Cover Steep Sites with Ground Covers in Your Home Garden Landscape" suggests more shrubs and perennials that homeowners might find useful as groundcovers for slopes.
Not only is this site relatively low maintenance, it has four-season visual appeal for passersby through the busy intersection. The shrubs and grass plant provide year-round color and texture to this planting while the perennials' bloom periods peak from mid-July through early August.
Georgene A. Bramlage - Suite 101 Landscaping Feature Writer and Topic Editor Free-lance Garden and Landscape Writer and Consultant
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