Groundcover can be attractive alternative to mulch

Sometimes mulch can be a bit too much.

Mulches retain moisture and restrain weeds and are great for protecting the roots of trees from lawn mower and edger cuts.

We're taught that mulch shouldn't be stacked up in a “volcano” mound around the tree base. But, even knowing the benefits and proper application of mulch, aren't there times when mulch is a bit of a mess?

Todd Jacobson, the Morton Arboretum's head of horticulture, supports the many benefits of mulch but also thinks groundcovers can be an attractive alternative.

“If you have a tree or shrub in a garden situation, groundcovers can look and work quite well,” he says.

Groundcovers can be more aesthetically pleasing than wood chips, and also can protect the tree roots. Low-growing plants also can retain moisture for the tree roots and, contrary to popular myth, do not compete for nutrients any more than turf that encroaches under the tree's dripline.

Dry shade — the typical environment under mature trees — is a challenge for growing many plants, but Jacobson points out hundreds of possibilities in the arboretum's famed Groundcover Garden. His favorites are Epimedium spp. and Euphorbia amygdaloides var. robbiae.

Epimedium spp., sometimes called bishop's hat, offers delicate, long-spurred flowers in spring that can resemble a clergyman's headdress. Numerous flower colors are available, depending on which cultivar is chosen. But the flowers are not its only attraction.

The heart-shaped foliage and wiry stems are drought tolerant and semi-evergreen, depending on the severity of our winters, with some cultivars exhibiting colored foliage on new emerging leaves during fall.

E. amygdaloides var. robbiae, or Robb's almond spurge, has showy chartreuse-colored bracts in spring that are complemented by its dark green, glossy leaves. The plant grows 18 to 24 inches tall, and, if protected, is semi-evergreen. Both plants are well-behaved in the garden and slowly colonize.

If you like semi-evergreen groundcovers, also consider Christmas fern (Polystichum acrostichoides), a native plant. This fern, which grows 1 to 2 feet tall, can tolerate dry to moist soils.

“You have to give it some love early on,” Jacobson warns, but once established, it flourishes.

Looking for some quick-spreading, reliable groundcover? Consider Liriope spicata, which reaches a height of 12 to 18 inches. Sometimes called lilyturf, the grasslike foliage spreads by runners and can grow aggressively. Put it in an area that is contained and you will have a reliable, semi-evergreen cover that is very adaptable and can be mowed just like regular grass — but you only have to mow it twice per season.

Other groundcovers that spread quickly include popular standbys such as English ivy, wintercreeper (Euonymus fortunei), pachysandra and common periwinkle. All are evergreen or semi-evergreen and form a dense mat.

Jacobson cautions that ivy has a tendency to climb up tree trunks, which can be a nuisance, but if you're willing to prune the wayward vines, the plants will happily coexist. He also points out that wintercreeper is very prone to Euonymus scale.

Less familiar groundcovers to try might include:

Ÿ Corydalis lutea: With its delicate toothed leaves, corydalis blue-green foliage somewhat resembles that of bleeding heart. Its light yellow flowers bloom from May to September. “It's definitely going to self-seed,” Jacobson warns; so plan to contain it, or make sure it has plenty of room.

Ÿ Veronica “Whitewater”: This new Chicagoland Grows selection of the popular speedwell plant forms a low-growing (4 to 6 inches) mat of glossy leaves with white flowers. Its leaves turn burgundy in the fall and are fairly tolerant of foot traffic.

Ÿ Sedges: “There's an endless number of sedges that tolerate shade really well,” says Jacobson. Straight-styled wood sedge (Carex radiata) is a cool season sedge with a mounded growth habit. Common oak sedge (C. pensylvanica), also a Midwest native, likes dappled sunlight and dry conditions.

Ÿ Pulmonaria: Its common name, lungwort, does not inspire visions of beauty, but this flowering perennial can be used as a partial shade groundcover. It needs more constant moisture than some of the other plants listed, but with its many cultivars, there is a flower color suited for every garden.

Jacobson notes that no groundcover is maintenance-free. Until they are firmly established and fully cover the area, you will have to keep up with the removal of weeds. But if you've grown tired of replacing mulch, or dislike circles of brown chips, consider a green alternative of living groundcovers.

Ÿ Cathy Maloney is a writer for the Morton Arboretum.