Plant Taxonomy of Liriope Plants:
The two varieties of liriope that are most popular in landscaping are:
- Liriope spicata
- Liriope muscari (named after Muscari botryoides, the botanical name for grape hyacinth, whose flower formation is similar)
Often associated with these two is a third short plant with grass-like blades called Ophiopogon. All three of these ground covers are commonly referred to by the names "monkey grass," "border grass," and "lilyturf." Since the genus name, Liriope is also often used virtually as a common name, below I refer to the plant in general as "liriope" plant (without italicizing).
Where a distinction needs to be drawn, I refer to one or the other species.
Liriope plants are herbaceous to semi-evergreen (depending on location) perennials. They are treated as an ornamental grass, even though they have traditionally been considered a member of the lily family, as the common name, "lilyturf" suggests (more recently, they have been placed in the Ruscaceae family). In terms of landscaping use, they are employed as a ground cover.
What This Ground Cover Looks Like and Where It Grows:
The blades of Liriope spicata reach, at most, 1 foot in height, with a narrower spread. This is a clump-forming perennial, which further associates it with ornamental grasses in people's minds. It has a spikey flower, ranging in color from white to blue and lavender. In autumn, it bears a dark berry. Flowers and berries or not, I consider this to be primarily an outdoor foliage plant.
The leaves are grass-like and often variegated (L. spicata 'Silver Dragon' is an example of a variety that has variegated leaves).
Liriope spicata can be grown in planting zones 4-10.
A Comparison Between L. spicata and L. muscari:
L. muscari is bigger than L. spicata. The former can reach a height of 18 inches and a width of 12 inches.
L. muscari is also less hardy (only to USDA growing zone 7). But the two are more similar than dissimilar, including the fact that both are native to the Far East.
Sun and Soil Requirements for Liriope Plants:
Liriope plants can be grown in partial shade, although they also double as sun-plants. They profit from water, but as long as you plant them in partial shade, they will tolerate relatively dry conditions. Either way, they need a well-drained soil. But these ground covers are, generally speaking, tough plants that spread quickly and easily, which accounts both for why they are loved and why they are hated (see the Caveat section below).
Liriope plant is a vigorous grower (see below). Keep after it if you want to restrict it to one area. Set up bamboo barriers or bury landscape edging to contain it and/or dig it up if it spreads where you don't want it. If you wish to use this plant as a ground cover in multiple areas of your landscaping, you can divide and transplant. Spring is listed as the best season for dividing. It is a deer-resistant ground cover.
A Caveat in Growing Liriope Plants:
Indeed, one common name for them is "creeping lilyturf": when you see "creeping" in a plant's name, that's often a red flag that it spreads aggressively.
Uses in Landscape Design:
Like many ground covers, three of the common uses for Liriope plants are:
For erosion-prevention, as edging plants, and for weed control.