These tough, living mulches fill awkward spaces, fight off weeds and offer a lovely grass alternative.
Let’s face it. The term “ground covers” doesn’t inspire a great deal of passion. For generations, ground covers have been regarded as plants for covering exposed soil in places where poor soil conditions, deep shade or steep slopes make it hard, or even impossible, to grow grass. But today, many gardeners recognize ground covers not only for their utility but their striking beauty as well.
Ideally, filling the spaces between plants with more plants instead of mulch provides color and textural contrast, increases habitat and food for beneficial insects and wildlife, beautifies the landscape, gives you ornamental foliage and various growth habits that are particularly attractive during the active growing season and – not surprisingly – might even provide winter interest to boot. If chosen correctly, a yard with established ground covers is a visual treat.
Over the course of my gardening days I have tried a variety of low-growing plants with varying results. I’ve fallen in love with some and have developed some rather nasty thoughts about others.
Here are my favorites, all hardy perennials. They include lovely bloomers, must-haves that are a bit aggressive but not invasive and a few fanciful ground huggers.
At the top of my list is an old-time favorite with versatile modern day use, Japanese spurge (Pachysandra terminalis). Evergreen and self-sustaining once established, it always looks good, and deer and rabbits avoid it. While long, sweeping beds of nothing but Japanese spurge can be monotonous; a well-manicured river swirling around trees, shrubs, large hostas or ferns is a sight to behold.
Growing 6-12 inches in height, pachysandra grows in nearly any well-drained soil, is fairly drought tolerant and spreads quickly to form a thick mat of glossy, coarsely toothed leaves. Small clusters of bottlebrush-shaped white flowers appear in early spring. Compact ‘Green Carpet’ and ‘Green Sheen’ have shinier leaves; ‘Variegata’ exhibits white edges, but all three are slower spreaders than the species.
Not every plant needs to be a show-off to be useful. Take gingers (Asarum spp.) for instance. Both North American wild ginger (A. canadense) and European wild ginger (A. europaeum) will go about their business of carpeting bare soil in damp spots without any coddling. I grow them primarily for their kidney-shaped leaves, since their brown jug-shaped flowers are hidden under the leaves.
Wild ginger, a dapper ground cover that blankets the earth with enthusiasm, has large, (up to 5-inch) wide leaves and a thick sturdy rootstock that forms a dense network of plants in any woodland setting. For me, the one priceless feature of this deciduous plant is that once established, it can fend off garlic mustard, an invasive thug with which I am in constant battle.
Ornamental European ginger, on the other hand, is the captivating heart-throb of the family. The handsome leaves are a shiny rich green; some varieties have exquisite texture while others are adorned with striking silvery patterns. The plants are susceptible to few pests, are quite drought tolerant once established and remain fresh all season long.
For the front of the border, the deceptively delicate dwarf astilbe (Astilbe chinensis ‘Pumila’) forms a compact mound of elegant, lacy leaves topped with wispy, stiffly upright, lavender-rose flower plumes. One of the last astilbes to bloom, it does best in moist soil but is one of the least likely astilbes to fry in hot, dry weather. It is also deer and rabbit resistant. One of the last astilbes to bloom, it does best in moist soil but is one of the least likely astilbes to fry in hot, dry weather.
The sweet-scented, bell-shaped white flowers of lily-of-the-valley (Convallaria majalis) can pack a powerful punch despite their diminutive size. Though completely comfortable in deep shade and easily grown under almost any condition, lily-of-the-valley prefers rich loamy soil and ample moisture.
Yes, it’s important to know that it can be invasive. And sited in full sun with no additional moisture, it can look bedraggled during the dog days of summer. But place it correctly, contain its spread with barriers, and you will be rewarded with one of spring’s most captivating ground covers.
As likeable as the common lily-of-the-valley may be, there are less aggressive but charming cultivars that will add additional sparkle and dimension to your garden. Worth seeking out are ‘Albomarginata’ with white-edged leaves, ‘Albostriata’ with cream striping or ‘Aureovariegata’ with yellow. But for me, the less invasive ‘Rosea’ spreading slowly in front of blooming azaleas can totally upstage them, especially when you realize that its flowers are pink.
For some of the cutest ground covers, try hens-and-chicks (Sempervivum cvs.) and stonecrop (Sedum spp). With succulent rosettes available in a painter’s palette of colors or covered with cobweb-like hairs and in a variety of sizes, it’s no wonder that hens-and-chicks are the ubiquitous choice for any gardener with a hot, free-draining spot of soil to fill.
Plants spread when the large rosette in the center (hen) produces offsets at the end of runners (chicks). Baby chicks can be plucked off and planted separately where they will quickly root and produce their own colonies.
Three exceptionally gorgeous sedums, part of the SunSparkler series that tolerates cold as well as heat, are ‘Lime Zinger’ (with bright lime-green leaves edged in cherry-red and pink blossoms), ‘Dazzleberry’ (with unusual smoky-blue foliage and giant raspberry-red flowerheads) and ‘Cherry Tart’ (with small, rounded cerise-red toned leaves and deep pink blooms). Butterfly magnets when in bloom, these deer-resistant plants are just under 6 inches high but quickly fill in an area up to 18 inches wide.
If you want a colorful, low-maintenance, long-blooming ground-hugging mat of rounded leaves, look no further than blue star creeper (Isotoma fluviatilis). Compact, 3-inch tall deciduous clumps spread carpets of sky-blue flowers between stepping-stones or bare ground. A deciduous plant that tolerates rather heavy foot traffic, it needs well-drained moist soil.
Thyme (Thymus spp.) plants are an immense family, known as much for their culinary properties as ornamental ones. The low-growing, spreading thymes are fabulous ground covers in spots where plants receive only light foot traffic. (Many are incredibly difficult to tell apart without the benefit of a label.) Planted in well draining soil, the 2-inch tall creeping thyme (T. praecox) forms wonderfully thick mats of dark green leaves bearing rounded carpets of pale to dark lavender flowers in summer. Other T. praecox cultivars bloom in white and shades of rosy pink.
Just remember, a flourishing ground cover planting depends not only on careful selection of plant material, but also on proper cultural practices. Selecting the right plant for the right place is the most important step in achieving success.
A version of this article appeared in print in Chicagoland Gardening January/February 2016.
Photography courtesy of Betty Earl, SunSparkler sedums, and Stepables.