Tough Groundcovers for Tough Sites
The dream job presents perfect soil, abundant sun and sufficient natural moisture...
The dream job presents perfect soil, abundant sun and sufficient natural moisture to sustain healthy plants. For the rest of your projects, however, you'll need to select tough plants that can withstand the whims of Mother Nature-and continue to please your clients.
Plants for difficult sites are important to prevent erosion and stabilize soil, and groundcovers can be the best choice for this type of application. Often, though, tough plants are required to fill those sites that cry out for a planting that provides pleasing aesthetics as well. Whether it's a case of soil stabilization or a backyard garden in a drought-prone area, sooner or later you'll be required to spec those plants that establish readily, grow in poor soils, and require little or no care once established.
Left, Comptonia (sweetfern), which spreads from underground stems, can handle salt and poor soils and still produce a generous cover of aromatic, fernlike leaves. Right, Although certain varieties may be aggressive, cultivars of Viola are popular groundcovers, providing rich color in bloom and remaining semi-evergreen in many regions.
The red flag here is that many of these characteristics are shared with selections known to be aggressive - or downright invasive. So it's critical that your choice be appropriate to the site and to the region. The rule of thumb? Know the plant before you spec.
Left, Crown vetch is capable of thriving in dry, infertile soils and is long lasting-characteristics of a good groundcover. Those attributes, however, also make this plant aggressive in many areas, so be sure to check your local list of invasives before opting for this selection. Middle, Glorious fall color is attainable even in shaded, dry areas with Virginia creeper (Parthenocissus quinquefolia). Right, Not to be confused with lookalike barren strawberry (Waldsteinia fragarioides), wild strawberry (Fragaria virginiana) bears edible fruit.
Left, Photo courtesy of Richard Old, XID Services, Inc.; Bugwood.org; Photo courtesy of Monrovia; Photo courtesy of Mary Ellen (Mel) Harte; Bugwood.org
The plants listed here are good choices for Minnesota and are hardy throughout the state, unless otherwise noted. We recognize that some may not be the best selections for your particular area. But there are plenty of fine plants from which to choose.
Left, if you need a plant for a large area, a woody groundcover like Rhus typhina (staghorn sumac) offers an impressive array of ornamental characteristics as well as tolerance of poor soils and drought. Right, excellent drought tolerance and attractive foliage make a plant with the unfortunate common name skunkbush sumac (Rhus trilobata) a good choice on sites where aggressiveness is not a problem.
Left, Photo courtesy of Monrovia; Right, Photo courtesy of Howard F. Schwartz, Colorado. State University; Bugwood.org
Mary Hockenberry Meyer is professor and extension horticulturist at the University of Minnesota, St. Paul. She has conducted extensive research on ornamental grasses and developed the web site http://miscanthus.cfans.umn.edu/, titled "Miscanthus: Ornamental and Invasive Grass." She also authored the book Ornamental Grasses for Cold Climates. Meyer can be reached at firstname.lastname@example.org.
Grasses as groundcovers
Smooth bromegrass (Bromus inermis) will rapidly cover a tough site, which is why it's used by highway departments to control difficult slopes. But it is invasive and will rapidly replace native vegetation.
Photo courtesy of Dave Powell, USDA Forest Service; Bugwood.org
Grasses are among the best groundcovers on most sunny sites. The grasses suggested here can be used in poor sites and in low maintenance situations. They need not be mowed.
Fine fescues tolerate poor soils, dry conditions and can be grown in sun or light shade. A mixture of several species is a good choice. Sheep fescue (Festuca ovina) is commonly found in sandy soils and is quite drought and shade tolerant. It is bunchy, but it can be seeded with other fescues such as red fescue (F. rubra), Chewings fescue (F. rubra var. commutata) and hard fescue (Festuca longifolia).
The following native grasses can also be used for permanent cover. You can mix them with other native flowering plants for a more pleasing effect. Canada wildrye (Elymus canadensis) covers the ground rapidly, spreading from underground stems, and has attractive nodding heads. It is fairly shade-tolerant. Side-oats grama (Bouteloua curtipendula) is a common dry prairie grass that can cover large areas and does well on steep slopes. It prefers full sun. Sand dropseed (Sporobolus cryptandrus), another dry prairie grass, can be planted either in sand or on heavier soils. It is and very drought-tolerant. A nonnative, smooth bromegrass (Bromus inermis) is used commonly by highway departments on poor sites because it covers slopes rapidly. However, bromegrass is very invasive and will replace native vegetation, so it is not recommended where native material is available.