Ground covers to avoid
One of my perennial beds is slowly being devoured by pachysandra. Should this ground cover be avoided? What other plants fall in this category of aggressive behavior?
Tom Carpenter, Kent Cliffs, NY
Aggressive: Japanese pachysandra.
Photo/Illustration: Michelle Gervais
Nancy Ondra, coauthor of The Perennial Gardener's Design Primer, responds: The very traits that make some plants popular ground covers—the ability to spread quickly, crowd out other plants, and grow practically anywhere—are the same ones that can earn them a reputation as a garden thug. As you’ve found out, Japanese pachysandra (Pachysandra terminalis, USDA Hardiness Zones 4–8) can be a menace in loose, rich garden soil, rapidly overgrowing less vigorous companions. If, however, you plant it by itself in the dry, root-filled soil under trees, you’ll likely never have a problem with it creeping out of control.
Bugleweed (Ajuga reptans, Zones 3–9), English ivy (Hedera helix, Zones 5–11), goutweed (Aegopodium podagraria, Zones 4–9), periwinkles (Vinca spp., Zones 7–9), wintercreeper (Euonymus fortunei, Zones 5–9), and yellow archangel (Lamium galeobdolon, Zones 4–8) are other commonly sold ground covers that can be seriously aggressive. In fact, a list of top-ten ground covers can read remarkably like a list of top-ten problem plants. Nurseries keep selling them because they’re cheap to purchase in quantity and practically guaranteed to grow.
Nonaggressive: Allegheny spurge.
Photo/Illustration: Jennifer Benner
So what’s a responsible gardener to do? First, do your homework before letting any plant loose in your garden. Phrases such as “spreads rapidly” and “grows anywhere” are clues that the plant might be a problem later. Also, consider your site. If you just have some gaps in an already-prepared garden bed, use annuals and tender perennials to fill in. Save ground covers for tough sites where you have trouble getting other plants to grow, such as spaces under shrubs or on steep slopes, and install some kind of edging around the area to prevent them from creeping into adjoining lawn and garden areas. Investigate some of the lesser-known ground covers, too, such as Allegheny spurge (Pachysandra procumbens, Zones 5–9). It grows in gently expanding clumps instead of creeping in all directions. Set these more-restrained plants at closer spacings to get a solid cover within a few years. They’ll cost more up front, but they’ll save you a lot of headaches in the long run. For more information on plant behavior, contact a master gardener in your area; you can reach one through your local cooperative extension office.
From Fine Gardening 111, pp. 71