Liriope, commonly known as lilyturf or border grass, is a highly favored perennial groundcover. Its popularity stems from its ability to thrive in varied conditions, providing year-round green foliage and late-season flowers. Understanding the plant’s root system is fundamental to successful gardening and placement, as it dictates how a specific variety will grow and must be managed.
Anatomy and Function of Liriope Roots
Liriope possesses a dense and complex below-ground structure that allows it to tolerate challenging environmental conditions. The plant features a root system composed of thick, fibrous roots that serve the primary functions of anchoring the plant and absorbing water and nutrients from the soil. This root mass typically occupies the upper 6 to 12 inches of the soil profile, forming a robust foundation.
Attached to these fibrous roots are scattered, small, round, or peanut-shaped structures known as tubers or corms. These fleshy swellings are not roots themselves but specialized storage organs. Their main function is to store water and starches, which the plant utilizes during periods of stress. This reserve capacity grants Liriope its notable resilience and ability to withstand extended drought conditions and poor soil quality.
Understanding Liriope’s Spreading Mechanism
The way Liriope spreads is directly tied to its root structure, and different species exhibit distinct growth patterns. The genus is primarily separated into two types: clumping and spreading varieties. The clumping variety, exemplified by Liriope muscari, forms tight, dense mounds that expand outward very slowly.
Liriope muscari achieves this gradual expansion through short stolons, which are surface runners that root close to the parent plant. This growth habit means the plant remains largely contained where it was initially planted. The fibrous root system of this type is advantageous for creating clean borders or edging along pathways where a contained appearance is desired.
Conversely, the spreading type, primarily Liriope spicata, is defined by its far more vigorous growth pattern. This species utilizes underground horizontal stems called rhizomes to colonize new areas. Rhizomes actively grow away from the main plant, sending up new shoots at intervals, which results in a dense, uniform mat of foliage.
This rhizomatous nature is why Liriope spicata can be considered aggressive in a garden setting. The underground stems can travel long distances, sometimes growing beneath obstacles like concrete, allowing the plant to quickly overtake adjacent lawn areas or flower beds.
Practical Management and Control
Managing Liriope effectively requires techniques tailored to its dense, tuberous root system and its spreading habit. For maintenance, a mature clump will eventually require division every few years for rejuvenation, which can be a physically demanding task. The concentrated mass of fibrous roots and water-filled tubers makes the root ball heavy and difficult to penetrate. Gardeners often need a sharp spade or knife to cut through the solid root mass when dividing the plant in early spring or late fall.
For the rhizomatous Liriope spicata, containment is necessary to prevent unwanted spread. Because the rhizomes can actively travel, installing a physical root barrier or deep edging is the most reliable method for keeping this variety within its designated area. This barrier should extend several inches into the soil to block the path of the traveling underground stems.
Removing established Liriope, especially the spreading kind, is also complicated by the root structure. The density of the root mat and the energy stored in the tubers make manual removal difficult. Simply pulling out the visible foliage will not work, as the plant can easily regrow from any remaining root fragments or tubers left behind in the soil. Complete control often requires digging out the entire connected root system.