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
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
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.
These perennials make great companions planted with lily-turf:
Lanceleaf coreopsis, Coreopsis lanceolata
Tulip, narcissus, crocus
Tall garden phlox, Phlox paniculta
Ajuga (plant in clumps)