By Charles Kidder
Lawns are undoubtedly the most common groundcovers, but generally when people use the term, they mean “something other than a lawn” that can cover the ground. We think of a covering that’s fairly low in height—six inches or perhaps up to a foot—and comprised of a single species. People also typically envision groundcovers as evergreen and running, i.e. spreading fairly quickly by vegetative means. While there are several old standby groundcovers, it’s not a bad idea to consider other options.
Compared to lawns, groundcovers do offer a couple of advantages. Certain species can be grown in shade, a place where lawns struggle. And they can cover a steep slope, where mowing is tricky. While lawns require frequent mowing, as well as periodic watering and feeding, established groundcovers are relatively low maintenance. From a design standpoint, they can provide a variety of colors and textures in the landscape. But groundcovers do have their darker sides, which are ignored at the gardener’s peril.
Groundcovers can be tough to maintain while they are getting established. Small plants that are placed six inches to a foot apart leave a lot of territory wide open to weed invasion, so gardeners have to be diligent about maintenance for the first couple of years, at least.
Even when groundcovers have taken a firm hold, they’re not always the “weed-smothering carpet!” that marketing hype would lead you to believe. To wit, English Ivy does indeed form what appears to be an impenetrable tangle after a few years. But if there is an oak or maple tree around, you’re likely to have a zillion little trees popping up right through the ivy—and no easy way to get rid of them.
The greatest virtue of some groundcover species is also their greatest vice. To go from a scattering of individual plants to a solid mass, they rely on one thing: rapid, if not rampant, spread. And, there is no OFF switch. Many novice gardeners are thrilled when you tell them that a plant spreads quickly, forgetting that in a few years their little darlings will be taking over the garden.
Given these caveats, let’s look at some popular groundcovers. Probably Number One on the lists of Most Used (or Most Despised) groundcovers is English Ivy, Hedera helix. (Some claim that the truly invasive bad boy plant is actually Irish Ivy, H. hibernica, although not every one agrees that is really a separate species.) English Ivy has evergreen leaves that look best in part shade; in full sun, they can look pretty beat up after a cold winter. As a vine, ivy has five-sided leaves. If left to climb, when it reaches a certain height it actually becomes shrubby and the leaves assume an oval shape. The plant flowers, fruits form, and birds spread the seeds. This is when the real trouble begins, as the ivy invades new areas. If you must plant ivy, do so where it is not near trees or walls that it can climb. Then you will only have to contend with unwanted growth on the ground.
Liriope, sometimes known as Monkey Grass or Lilyturf, rivals English Ivy as the most widely planted groundcover, especially in the South. Its evergreen grass-like leaves provide a fine texture year-round, and the spikes of purple or white flowers are a bonus in late summer. Liriope is happy in shade; it will take sun, but looks ragged at winter’s end. There are two species commonly available, and it’s important to know which you’re getting. Liriope muscari spreads relatively slowly and can reasonably be planted near other plants. Liriope spicata, or creeping lilyturf, does far more than creep, leaping and running through the garden. I would not recommend planting this species unless it is bounded by concrete. In some states both species are listed as invasive, although they weren’t on Virginia’s list when I recently checked. Nevertheless, I have seen Liriope seedlings pop up in my yard, so beware.
If you want more a well-behaved alternative to Liriope, consider the genus Carex. There are perhaps a thousand species in this group of sedges, grass-like plants that are native to much of the world. Some of the Asian varieties come in interesting colors and are frequently used in container arrangements. But there are also many North American native species such as C. pennsylvanica and C. appalachica that make good groundcovers in shady areas.
Pachysandra terminalis is a commonly planted Asian groundcover that looks best in shade. It has a more refined look than ivy or liriope, but can also be an aggressive spreader. ‘Green Sheen’ is a variety that does better in Southern heat and spreads more slowly. Unfortunately, pachysandra is susceptible to various diseases that can be hard to combat. P. procumbens, sometimes known as Allegheny Spurge, is a native species that sadly is not much seen in cultivation. The foliage is not reliably evergreen in cold weather, but the white flower spikes are more showy than those of its Asian cousin.
Periwinkle (Vinca minor), with its delicate foliage and blue flowers, is a deceptively innocent-looking little plant. It is not a rampant spreader, but can gradually creep into the woods and take over native environments. I would only use it if you can keep it away from natural areas. When groundcovers like vinca and ivy invade the woods, they form a monoculture that smothers native wildflowers.
As an alternative to the usual suspects, feel free to use plants that are not typically considered groundcovers. The various Helleborus species and hybrids (Hellebores or Lenten Roses), are generally evergreen and have long-lasting flowers in late winter. If you don’t get carried away with mulch, you will see many seedlings coming up beneath your hellebores. Leave a few where they are, and the patch will gradually spread to cover the ground; transplant others next fall to hasten the process.
And feel free to stick some Irish Ivy in your hat on St. Patrick’s Day.
