The plant genus Liriope is a popular grass-like perennial frequently used in landscaping, but its common name often causes confusion among gardeners. While it is not a true grass, this tough, evergreen Asian native is widely planted for its tidy foliage and late-season flowers. The primary source of ambiguity comes from the interchangeable use of the informal name “Monkey Grass” to describe it and a closely related plant.
Clarifying the Common Names
The question of whether Liriope is “Monkey Grass” is complicated because the term is used colloquially for two separate, though similar, plant genera. “Monkey Grass” serves as a common umbrella term that can refer to both Liriope and Ophiopogon. Both are grass-like perennials native to East Asia, which contributes to their frequent misidentification. Ophiopogon, generally known as Mondo Grass, is a distinct genus separate from Liriope, which is also commonly called Lilyturf.
Liriope plants are generally larger, growing 12 to 18 inches tall with wider leaves. Mondo Grass is usually shorter, growing between 6 and 12 inches high, with narrower foliage. Another key difference is in the flowers: Liriope produces showy flower spikes that stand above the foliage, while Mondo Grass blooms are smaller and often hidden within the leaves. Liriope is the plant most often sold under the common name “Monkey Grass” in the United States.
Distinguishing the Key Species
The Liriope genus contains two main species widely cultivated in gardens that are differentiated primarily by their growth habits. Liriope muscari, commonly called Big Blue Lilyturf, is the clumping variety, forming dense, compact mounds that slowly expand outward. Its foliage tends to be wider, and its lavender or white flower spikes are typically held high above the leaves in late summer and early autumn.
The second common species, Liriope spicata, is known as Creeping Lilyturf because of its aggressive spreading nature. This variety spreads rapidly by sending out underground stems, called rhizomes, which form new plants a short distance from the parent plant. L. spicata generally has narrower leaves and its flower spikes are often shorter, sometimes partially obscured by the foliage. The distinction in growth habit is the most consequential difference, as L. muscari maintains a tidy appearance while L. spicata quickly fills in large areas.
Essential Requirements for Growth
Liriope is a low-maintenance choice that performs optimally when planted in well-drained soil with a pH that is slightly acidic to neutral. While it tolerates a wide range of light, from full sun to deep shade, plants generally exhibit their best growth and flowering when situated in partial shade with some exposure to morning sunlight.
Once established, Liriope is drought-tolerant, but new plantings require consistent moisture during their first growing season to develop a strong root system. A balanced fertilizer, such as a 10-10-10 formula, can be applied in early spring to encourage healthy growth, though it is not necessary in fertile soil. The most common maintenance task is shearing the foliage back to the ground in late winter or early spring before new growth begins, which allows fresh, new green blades to emerge cleanly.
Managing Spread and Landscaping Utility
Selecting the appropriate species is necessary to manage the plant’s potential spread. Liriope muscari is used for defined borders along walkways or garden beds because its clumping habit keeps it contained. Conversely, the rapid, rhizomatous spread of Liriope spicata makes it the better choice for large-scale groundcover applications, especially on slopes or banks where erosion control is necessary.
If the spreading nature of L. spicata is a concern, installing a physical barrier, such as buried landscape edging, can help restrict its aggressive expansion. This plant is a durable selection for challenging locations, as it tolerates air pollution and is not typically favored by deer or rabbits. Its resilience and general lack of severe insect or disease problems mean it provides dependable, multi-season interest in the landscape.