Liriope, often called lilyturf or monkey grass, is a widely used perennial groundcover valued for its grass-like foliage and resilience in challenging landscape conditions. Understanding how big Liriope gets requires looking at the species selected and the environment it grows in. The typical height range for most varieties falls between 10 and 18 inches, with the horizontal spread being the most unpredictable dimension.
Clumping vs Spreading Growth Habits
The most significant factor determining Liriope’s maximum spread is its species, which dictates whether it exhibits a clumping or a spreading growth habit. The two most common species used in landscaping are Liriope muscari and Liriope spicata, which behave very differently. Liriope muscari, often called Big Blue Lilyturf, is a clumping variety that slowly expands from the center, forming predictable, well-defined mounds.
This species has a fibrous root system, causing it to grow outward gradually via short stolons. A typical mature clump of L. muscari reaches a height of 12 to 18 inches and a similar width, making it ideal for edging and borders. Cultivars like ‘Evergreen Giant’ sometimes reach 18 to 24 inches but maintain the tight-clumping form. This controlled growth makes L. muscari the preferred choice when a neat, contained footprint is desired.
In contrast, Liriope spicata is known as Creeping Lilyturf because of its aggressively spreading nature, powered by underground stems called rhizomes. These rhizomes travel beneath the soil surface, sending up new shoots that allow the plant to colonize large areas quickly. While L. spicata typically grows 9 to 15 inches tall, its horizontal spread is practically unlimited if left unchecked. The rapid, mat-forming growth makes this species an excellent choice for erosion control or covering large areas.
Factors Influencing Maximum Size
Beyond the genetic blueprint of its species, Liriope’s size is influenced by the environmental conditions of its planting site. Access to light plays a role; Liriope tolerates deep shade to full sun, but plants grown in partial sun often exhibit the most robust growth and flower production. Plants in deep shade may become slightly taller as their leaves elongate to reach more light.
Soil quality also affects vigor. While Liriope tolerates poor soils, including heavy clay or sand, it thrives in moist, fertile, and well-drained soil. When the soil is rich in organic matter and consistently watered, the plant’s growth rate and overall dimensions are maximized. Conversely, Liriope planted in poor, compacted, or extremely dry soil will be smaller and less vigorous. Adequate moisture is important during the plant’s first season to establish a strong root system, after which it becomes highly drought-tolerant.
Managing and Restricting Growth
Managing Liriope’s size primarily involves controlling its horizontal spread and refreshing its appearance. Annual maintenance involves pruning the foliage in late winter or early spring to remove old, tattered leaves. Trimming the foliage back to a few inches above the crown allows new, fresh growth to emerge unhindered.
To control the size and spread of the clumping Liriope muscari, division is the most effective method, typically performed every three to five years. Digging up the clump and separating the root mass into smaller sections maintains the plant’s vigor and prevents the clumps from becoming too large. Controlling the aggressive spread of Liriope spicata requires proactive measures due to its rhizomatous habit. For this spreading species, installing a physical root barrier, such as landscape edging buried 12 to 18 inches deep, is necessary to restrict horizontal expansion.