December / 2000
At Home in the Garden

Lily-turf groundcover
by:  

As the temperatures cooled and the growing season started to slow down, I took a moment to review what plants stood out in performance or popularity from all the gardens I had the opportunity to work in and enjoy. At first the list was short but started to grow when I decided to ask everyone I work with what plants they thought were the best this year. We all chose different plants and for different reasons.

One group of plants seemed to prevail in popularity this year-groundcovers. What purpose do groundcovers serve in the garden? As we strive to maintain our gardens our biggest problem always seems to be controlling the weeds. A lush groundcover planting can suppress weed growth and provides an excellent surface to move the eye throughout the garden. They also provide a sense of depth and richness and provide an excellent surface to show off colorful shrubs or perennials.

The list of available hardy groundcovers is fairly short when you think of only the traditional ones like English ivy, pachysandra, and vinca vine. I encourage you to think beyond traditionalism and consider such perennials as dianthus, plumbago or leadwort, chrysogonum 'Green & Gold,' creeping thyme, or sweet autumn clematis and plant them in large groups to serve as a groundcover. Traditionally groundcovers are thought of as evergreen and while many are, deciduous ones can provide the same weed suppression and sense of depth and richness as their evergreen counterparts.

Certainly the most popular and versatile groundcover today is liriope, also called lily-turf or monkey grass. Of the five species available only two are commonly available, Liriope muscari, or blue lily-turf, and Liriope spicata, or creeping lily-turf. Both will grow in a wide range of conditions from full sun to dense shade, are extremely tolerant of heat and drought, and have very few, if any, insect or disease problems. These grass-like groundcovers are evergreen but should be trimmed back late each winter to accommodate the new flush of growth in early spring.

Blue lily-turf is a clumping form but can form a tight mass over time. It ranges in height, depending on soil conditions, from 12 to 18 inches. The flowers, which appear in late July or August, are lilac to medium-purple and the seeds, which are black, color up in early fall. There are several excellent cultivars available like 'Big Blue' and 'Monroe White' (a white flowering form) as well as the extremely popular, naturally occurring variation, variegata. The leaves of variegata have creamy white margins and can provide a nice bright mass or border in a shady garden. This variety, like 'Monroe White,' does not spread as aggressively as the species.

One cultivar that has caught my attention in recent years is Liriope muscari 'Christmas Tree' with lilac flowers that are wider at the base and taper to the tip like the traditional shape of a Christmas tree.

Creeping lily-turf is less commonly available and very similar to blue lily-turf. The leaf blades are slightly narrower and the flowers are a pale lilac-almost white. While both are spread by stoloniferous roots (whereby the root runs underground and a new plant forms where the root surfaces), Liriope spicata, or creeping lily-turf, is considered aggressive and spreads quickly to form a thick mass even in dense shade. This aggressive habit makes this variety unsuitable as a border planting because it will take over in no time at all.

I have used all kinds of plants as groundcovers in my designs, including the popular lily-turf. It has certainly outperformed many of the traditional evergreen groundcovers in a harsh, dry, or sunny environment. I have also found it to be a great plant for use as filler foliage in container planting and hanging baskets with seasonal color. I use it quite frequently in containers with pansies in the fall and winter so that in January and February when Mother Nature burns back the pansies temporarily, the lily-turf is there filling in the gaps.

As winter progresses look deep into your garden and see if you can imagine a place where a plant that you love can grow in a mass as a groundcover. In the spring plant it and watch it fill in. While it may not be traditional or popular, if it performs well it will give your garden a sense of diversity and a personality all its own.

Complementary Perennials
These perennials make great companions planted with lily-turf:
Sun Gardens
Lanceleaf coreopsis, Coreopsis lanceolata
Tulip, narcissus, crocus
Tall garden phlox, Phlox paniculta

Shade Gardens
Hosta
Ajuga (plant in clumps)
Meadow rue