Covering Ground with Natives

Gardeners and gardening publications are talking about the benefits of native plants. It sounds appealing to incorporate plants that will look good and contribute positively to the surrounding ecosystem. As with any new garden endeavor, the amount of information and opinions may seem overwhelming and you might be hesitant to “start over” with natives. I’d like to propose that an easy way to get started without having to undo anything you have already done is to introduce native ground covers. Think of them as a gateway to the world of native plants with easy entry.

Ground covers are often overlooked in planning an ornamental garden as we focus on the larger plants and shrubs. However, ground covers add a layer of diversity both in color and texture for our aesthetic pleasure. In addition, they add a source of food for creatures big and small, and habitat for those living close to the ground. They suppress weeds once they reach full coverage, and they can help prevent erosion. Many people use mulch to do some of these jobs. Areas beneath shrubs and trees that you are currently mulching and/or weeding are good places to introduce native ground covers. Another option is to incorporate them around the edges of your lawn or use them to replace lawn areas that are failing, especially in the shade. These two situations, however, are drastically different and require unique strategies. In the first example, you need plants that will not suffocate your existing garden, and in the latter, you need plants that will “take over."

One definition of a ground cover is a plant that spreads to form a colony of uniform foliage. If this is the look you want, a single species with an aggressive root system is in order. A word of caution here is that many of the plants that spread quickly while excluding all else (native or non-native alike) may become problematic when they grow beyond the bounds you have set for them and may not be good neighbors to existing garden plants. This is typically not a problem if you like their looks and low-maintenance habit when the goal is to shrink a lawn. Ferns are my number one recommendation for this situation. Clonal species (those that spread by shoots and roots) like hay-scented, beech and New York fern have a very consistent look and are adaptable to many light and moisture conditions, with the exception of dry sun.

Aggressive flowering plants in this category include big-leaf aster, which covers the ground with large heart-shaped leaves all summer before sparingly sending up flowering stalks in the fall, sessile-leaved bellwort, which blooms early in the summer looking like a miniature Solomon’s seal but needs shade for the foliage to last through fall, or one of several species of pussytoes with small hairy, grey-green leaves and a stalk of white flowers in early June.

Some less-aggressive clonal ferns are maidenhair fern for higher pH soils and oak fern which is so delicate it would be hard to imagine it ever becoming a nuisance. These would be fine in a garden bed or under a shrub or tree but the trade-off is less weed suppression. Flowering natives in this category are many which mainly spread by shoots, but may not grow as densely as the more domineering ferns to exclude all weeds if not perfectly happy with their growing conditions. Planting a combination of natives may help to overcome this issue and provide increased diversity, flowering period, and color. For a moist shady spot try wood sorrel, twinflower, or goldthread, and add one of many native violets which spread by seed rather than shoots. For dry shade choose from woodland natives like Pennsylvania sedge, Canada mayflower, bunchberry, wintergreen, or partridgeberry.

Ground covers for dry sun include bearberry, three-toothed cinquefoil, and the ethereal purple love grass which tends to self-seed (below, left). For moist sun, turn to some of our most beautiful wetland plants like Canada anemone (below, right), swamp candles, cranberry (below, middle) or marsh marigold which blooms around Memorial Day and forms a neat clump. Possible combinations are many depending on site conditions, height preference and aesthetics. Vines like virgin’s bower and Virginia creeper also make good ground covers, but they do tend to climb on nearby plants. Whether you want to rely on single plant to get the job done or a combination of compatible plants will be up to you. Remember that our natives are quite adaptable, especially when grown in fertile garden soil, so don’t be afraid to push the boundaries.

To find out more about each of these plants like height, bloom color, and preferred garden conditions, you can look them up online (many are profiled on the Native Gardens of Blue Hill website) or turn to William Cullina’s “Wildflowers: a guide to growing and propagating native wildflowers of North America or Wild Seed Project’s “Native Ground Covers for Northeast Landscapes” for more information.

Many of the plants I mentioned are readily available at your local nursery. Some you may already have on your property and are easily divided and transplantable, and some you will have to seek out (see list of growers below). Start with a few plants and observe how well they establish in your garden conditions. If they are well suited, that may be all that is needed. If they haven’t made significant progress in covering the ground by their second season, try adding another species to the area. By incrementally adding, transplanting and dividing the ground covers in your garden you will learn about them more deeply while you enjoy their aesthetic and ecological benefits, and have a high chance of success.

The spring plant sale at Native Gardens of Blue Hill is usually Saturday after Memorial Day from 9–noon at Bagaduce Music in Blue Hill. Also, many of our local growers sell their plants at the various farmers’ markets. Visit the websites of the growers to find out more: 5-Star Orchard in Brooklin, Northern Bay Organics in Penobscot, Honey Petal Plants in Brooks, Rebel Hill Farm in Liberty, Blue Aster Native Plants in South China, After the Fall Farm and Rooted Elements in Montville, Bas Rouge Farm in Orono, and our newest addition, Trout Lily Collective in Waldoboro. All are small growers who are committed to growing natives sustainably. They themselves are also a wealth of information.

Once you become familiar with some of our excellent native ground covers you will be ready to start planting the many ecologically beneficial, garden-worthy herbs and shrubs native to Maine.

Ground covers I mention with scientific name in order they appear.

Common name	Scientific name
Hayscented fern	Dennsteadia punctilobula
Beech fern	Phegopteris connectilis
New York fern	Thelypteris (Parathelypteris) noveboracensis
Big-leaved aster	Eurybia macrophylla
Sessile-leaved bellwort	Uvularia sessilifolia
Field or Plantain-leaved pussytoes	Antennaria neglecta or plantaginifolia
Maidenhair fern	Athyrium angustifolia
Oak fern	Gymnocarpium dryopteris
Wood sorrel	Oxalis montana
Twinflower	Linnaea borealis
Goldthread	Coptis trifolia
Violets	Viola cuculata, sororia, labradorica
Pennsylvania sedge	Carex pensylvanica
Canada mayflower	Maianthemum canadense
Bunchberry	Cornus canadensis
Wintergreen	Gaultheria procumbens
Partridgeberry	Mitchella repens
Bearberry	Arctostaphylos uva-ursi
Three-toothed cinquefoil	Sibbaldiopsis tridentata
Purple love grass	Eragrostis spectabilis
Canada anemone	Anemone canadensis
Swamp candles	Lysimachia terrestris
Large or Small-leaved cranberry	Vaccinium macrocarpon, oxycoccos
Marsh marigold	Caltha palustris
Virgin’s bower	Clematis virginiana
Virginia creeper	Parthenocissus quinquifolia