Native Groundcovers Can Solve Tough Challenges in the Landscape
Some of the most challenging questions received by the Garden Hotline have to do with choosing groundcovers for tough locations, such as a sunny slope, flanked at the top by a road where ice melt products are applied in the winter. Quite often, the caller is an older adult who is unable to do the maintenance their slope currently requires.
This gardener needs a groundcover that will help control water runoff and erosion, tolerate salt spray, thrive in the hot sun, and be low maintenance. Additionally, the groundcover should be evergreen and needs to spread quickly on its own.
Surprisingly, there is a nice selection of native groundcovers that can work to solve these challenges, are aesthetically pleasing, and contribute to a healthy ecosystem that supports native wildlife. In many ways, choosing native plants is the best solution possible since many have deeper roots and, once established, may require less water and maintenance than non-native plants.
Some Selections for This Scenario Are:
Native Grasses and Sedges, Which are Especially Good for Slopes
- River oats (Chasmanthium latifolium) – very good for slopes because it develops a firm root mass; provides winter interest; readily self-sows
- Little bluestem grass (Schizachyrium scoparium) – a clumping grass that is blue-green in spring and coppery in autumn; wonderful planted in drifts; reseeds readily
- Muhly grass (Muhlenbergia capillaris) – a clumping grass with dark green leaves; stems 2 to 3 feet tall; pink, airy, open blooms appear to float above fall foliage; tolerates heat, drought, poor soil, and salt
- Pennsylvania sedge (Carex pensylvanica) – a good lawn substitute; has a soft, weeping appearance; extremely low maintenance, but looks best if weed-whacked or mowed to about 3 inches tall in late winter
Native Perennials
- Coral bells (Heuchera spp.) – all varieties are good but Heuchera villosa is more heat and deer-tolerant; blooms from June through the end of summer
- Prickly pear (Opuntia spp.) – very heat tolerant; adds interest; spreads slowly, easy to propagate
- Golden groundsel (Packera aurea) – reseeds and spreads quickly; divide in the spring after flowering; deer and rabbit resistant; attractive yellow spring flowers
- Dwarf tickseed (Coreopsis auriculata 'Nana') – hardy; low-growing; plants spread and form colonies via runners; foliage rosettes persist through most of the winter
- Wild violet (Viola spp.) – blooms in early spring; somewhat salt tolerant; expands in clumps through underground rhizomes; dig and divide from spring through fall for more plants
- Creeping phlox (Phlox stolonifera) – good for erosion control but likes well-draining soil; keep well-watered in the first year and thereafter it's drought tolerant
Conifer
- Common juniper (Juniperus communis) – a spreading shrub; 3 to 6 feet tall; extremely hardy and adaptable to diverse soil and climatic conditions; does well on rocky slopes; very drought tolerant; somewhat tolerant of salt
If possible, avoid planting one single species, or monoculture, to cover the entire area. If disease or pest problems arise, the entire monoculture planting may be killed. Instead, consider planting drifts or groups of single species, providing a patchwork-quilt effect. This is very pleasing to the eye and healthier for the plants.
Proper site and soil preparation are extremely important to ensure low maintenance in the future. Grass and weeds should be removed, and the soil should be tested to determine if any fertilizers or amendments are needed. Follow the instructions from the testing lab. (For information on soil testing, contact the Penn State Extension Garden Hotline in your county.) After the site is prepared, and if practical, leave the area unplanted for about 2-3 weeks. During this time, perennial weeds may regrow from their roots and can easily be removed.
It is not recommended to use plastic or synthetic landscape cloth on top of or under the soil. These can increase erosion and water runoff. Plastic can also negatively impact soil health. They can become big problems in the future if they become exposed or if weeds grow up through them. Many homeowners have regretted using plastic or synthetics on a slope.
Plant most groundcovers in the spring or fall, to allow the plants to become established before the heat and stress of the summer. Although native plants may require less water than non-natives, a new planting must be watered until it is established. The spacing of plants depends on the plant’s habit, rate of growth, and propensity to spread and/or reseed. Allow more space between faster-growing groundcovers. When planting on steep slopes, you can plant through a natural fiber netting to hold the soil in place. These natural fiber nettings, made of biodegradable coir or plant fiber, will disappear completely in time. By then, the deep-rooted, native plants will be firmly anchored.
To control weeds, apply at least two inches of mulch after planting, preferably wood chips, undyed shredded bark, pine needles, or composted leaves. This also helps to keep the soil moist and the roots cool. After the first year, water-established plants as needed only during dry periods in late spring through fall. Most native groundcovers will require a minimum amount of maintenance.
Lastly, this article only discussed low-growing, native, perennial groundcovers. Keep in mind there are many wonderful taller native perennials, shrubs, and trees that do an outstanding job of reducing soil erosion on a slope. Some can also tolerate salt. Additional research will result in many recommendations.
Resources for Finding Native Plants
Ladybird Johnson Wildflower Center at the University of Texas
Pennsylvania Department of Conservation & Natural Resources (DCNR)
