Fill the gaps in your garden with these expert choices for sunny or shady sites.
Ground covers are a gardener's utility plants-we generally don't grow them unless we need them. But maybe we should use ground covers more. These low-growing plants can beautify a spot where nothing seems to fit, and can cover steep slopes to help prevent erosion problems. Plus, they're a top choice if you want to reduce the size of your lawn, or have a shady spot where grass just won't grow.
If you have a patch of ground that needs covering, consider these expert picks:
There's almost no limit when it comes to ground covers for sunny sites. Mike Heger, owner of Ambergate Gardens (www.ambergategardens.com) in Chaska, Minnesota, says his favorites include cranesbills (Geranium spp). "One attractive species is G. sanguineum, which bears magenta-pink flowers through the summer and brilliant red autumn foliage," Heger says. He also likes bellflowers (Campanula spp), with their charming blue or white, bell-shaped flowers, and low-growing filipendulas (Filipendula vulgaris) with feather-like flowers and attractively cut foliage.
Carla Allen, owner of South Cove Nursery (www.klis.com/scove ) in Yarmouth, Nova Scotia, likes various thymes (Thymus spp.) to cover her ground. "Woolly thyme (T. pseudolanuginosus) is my favorite because of the color and texture-so many other colors play well against its fuzzy gray leaves," she says. In addition to their colors and textures, many thymes offer pleasant fragrances.
Gardeners in the South need plants that will stand up to heat and humidity, such as lilyturf (Liriope spp.), which has grassy foliage and spikes of purple flowers. Carl Schoenfeld, owner of Yucca Do Nursery (www.yuccado.com) in Hempstead, Texas, likes Carex flaccosperma, a native sedge with blue foliage. "It's evergreen and makes a great ground cover in sun or deep shade," he says. Another choice is 6-inch-tall Manfreda variegata. It tolerates full sun or light shade, says Schoenfeld, and "it has fabulous aloelike spotted leaves with undulating edges-very unusual."
Dwarf daylilies (Hemerocallis spp.) are an old standby sometimes overlooked. "They're fantastic ground covers, but a little taller than most" says Allen. Newer cultivars such as ‘Woodside Ruby' can help extend the blooming season into late summer and come in a range of colors from deep red to soft pink.
Another favorite ground cover is silvery-leafed lamb's ears (Stachys byzantina). In the right site, it happily spreads and sets off nearby plants with its soft gray color. For a mossy texture, consider creeping phlox (Phlox subulata). It has blooms in shades of pink, white, and blue in early spring. Another fine choice for pink, white, or blue blooms is ajuga (Ajuga spp.)-especially the variegated forms.
Ground covers seem to receive their greatest calling in shady spots for areas where grass won't grow well. Luckily, there is a host of choices for shade.
Dana Moore, owner of Blue Moon Nursery (www.bluemoonnursery.com ) in Preston, Washington, likes bigfoot geranium (Geranium macrorrhizum). "It makes a nice, wonderfully dense ground cover, even in dry shade," she says. Bigfoot geraniums bear clusters of pink flowers in early summer. They have attractive foliage that turns reddish-orange in autumn.
Heger says, "The best choice for shade, as far as I'm concerned, is our native wild ginger, Asarum canadense." It has fuzzy, heart-shaped leaves and hidden springtime flowers. (A relative, European wild ginger, A. europaeum, stays evergreen in Zones 4 to 8). More of Heger's picks include autumn-flowering white wood aster (Aster divaricatus), and sweet woodruff (Galium oderatum) with its attractive scented foliage and springtime clusters of small white flowers.
While you might not think of them as ground covers, hostas (Hosta spp.) are also an excellent choice for shade. "Very few weeds can make their way through those great big floppy leaves," Allen says. You can use any hosta as a ground cover, from small-statured ‘Ginko Craig' to large ‘Frances Williams', depending on how much room you have. Southern gardeners who can't grow hostas don't need to miss out, however. Schoenfeld suggests growing Drimiopsis maculata, also called South African hosta. "It's a hosta-like plant with purple-spotted, fleshy, dark green, healthy-looking leaves. It grows well in deep shade and is very drought tolerant."
For dense shade, Schoenfeld suggests a Mexican rain lily, Zephryanthes sp. Labuffarosa. It bears dense evergreen grass-like foliage and pink or white flowers in summer ("So thick they look like snow," he says). (Gardeners outside of Zones 7b to 10 can grow this bulb as a houseplant.)
Other shady standbys include sweet-scented lily-of-the-valley (Convallaria majalis), vinca (Vinca minor or V. major), fast-spreading bishop's weed (Aegopodium podagraria ‘Variegata'), and pink- or white-flowering dead nettle (Lamium maculatum). For lots of blooms, don't forget goldenstar, Chrysogonum virginianum. It blooms with daisylike flowers all summer.
Pigsqueak (Bergenia spp.) with springtime pink or white flowers, has evergreen foliage that takes on purple or red tones for added winter interest. (Its name comes from the sound the foliage makes when you rub it briskly.)
As you decide which ground cover to use, consider all of its qualities. For example, if it's a large site, you can plant something that grows taller-even to several feet tall. Smaller sites may require a lower-growing species, however.
While most of us are attracted to flowers, most ground covers only flower for a short time. To compensate, take a good look at the foliage. For instance, you might pick a variegated cultivar of vinca over a green-leafed type to add more color interest, or you might use a fine-textured ground cover such as a perennial geranium or a thyme around shrubs or plants with larger, coarser leaves.
Remember that many ground covers are spreaders. Check with the nursery or your extension service to be sure they don't become rampant in your area.
Clear the area of weeds before you plant ground covers. Weed killers broadly applied to the area after planting will kill both ground covers and weeds.)
Place plants just enough apart to match their mature width, so they'll fill in quickly.
Use a pre-emergence herbicide to prevent weed seeds from sprouting between the plants. (But don't use pre-emergence herbicides if you plant ground covers from seed.)
After planting, spread a 1- to 2-inch-deep layer of mulch between the plants to deter weeds.
For added interest, interplant spring bulbs such as muscari or narcissus with ground covers, which help mask the fading foliage of the bulbs after they bloom.
To cover an area quickly, set plants just enough apart to match their mature width.
If space is limited, you may want to contain aggressive plants before they spread too far. Try one of the following techniques:
Sink root barriers into the soil (made from wood, metal, or other materials). For most perennials, sink barriers at least a foot deep.
Grow aggressive plants in containers; sink the containers into the ground.
Dig a trench at least 8 inches deep where ground cover growth is to end. Maintain the border by running a hoe through the trench once a week.
Glorious Ground Covers
Zones 4 to 8; magenta flowers; foliage turns red in autumn
Zones 4 to 7; white or blue flowers
Zones 4 to 9; fluffy white flowers
Zones 4 to 9; scented foliage
Zones 5 to 10; tough grower
Zone 8 to 10; interesting foliage
Zones 3 to 10; flowers in a variety of colors
Zones 4 to 8; fuzzy silver foliage
Zones 2 to 8; heart-shaped foliage
White wood aster
Zones 4 to 8; autumn blooms
Zones 5 to 8; fragrant flowers and foliage
Zones 3 to 8; attractive foliage
Zones 7 to 11; attractive blooms
Zones 4 to 9; attractive blooms
Zones 2 to 7; fast spreader