Liriope, commonly known as Lilyturf or Monkey Grass, is a widely used ornamental groundcover. The plant’s success and the challenges it presents to gardeners are entirely dependent upon its unique subterranean structure. Understanding how this perennial utilizes its roots for resource storage and lateral movement is the foundation for effective cultivation and management.
Root System Anatomy and Water Storage
The Liriope plant anchors itself with a dense, fibrous root system that extends into the upper 6 to 12 inches of the soil. Along these roots, it develops small, fleshy, peanut-shaped tubers that function as specialized storage organs. These tubers are packed with reserve water and carbohydrates, allowing Liriope to survive extended periods of heat and drought.
This storage capacity is the primary mechanism behind the plant’s durability and resilience. Beyond water retention, the plant’s ability to propagate is determined by underground stems called rhizomes, which are distinct from the water-storing tubers. The two most common species exhibit different growth habits based on the activity of these spreading stems.
Spread, Growth Habit, and Groundcover Function
The type of underground stem determines whether a Liriope variety forms a tight cluster or spreads aggressively. Liriope muscari, often called Big Blue Lilyturf, is a clumping variety that utilizes short, radiating rhizomes or stolons, resulting in a gradual expansion of the original crown. This controlled growth habit makes L. muscari a preferred selection for formal edging and defined borders where containment is required.
In contrast, Liriope spicata, known as Creeping Lilyturf, employs long, fast-growing rhizomes that aggressively colonize the surrounding soil. These horizontal stems allow the plant to spread rapidly and indefinitely, often covering a wide area in a short period. This expansion makes L. spicata highly effective for fast groundcover coverage, mass plantings, and stabilizing slopes to control soil erosion.
The aggressive lateral spread of the running variety is a direct result of its extensive rhizome network. Because L. spicata is a rapid colonizer, it can be invasive in garden beds, displacing other plants and requiring careful placement. The clumping varieties maintain a more predictable footprint, making them suitable for tighter landscape designs.
Management and Control Strategies
Managing Liriope successfully requires techniques that address its dual root structure of fibrous roots, tubers, and rhizomes. For clumping varieties, division is the primary method for propagation and maintaining plant vigor when the dense roots become overcrowded. This involves digging up the entire clump and using a shovel or knife to separate the root ball into smaller sections, which can then be replanted.
To contain the aggressive L. spicata varieties, gardeners must use physical root barriers, such as buried landscape edging, to block the path of the spreading rhizomes. These barriers should be installed deep enough to prevent the underground stems from simply growing underneath, with depths up to 18 inches sometimes recommended for effective control. Without a barrier, L. spicata will expand into adjacent turf or planting beds.
Complete Removal
Removing Liriope can be difficult because the plant regenerates readily from small subterranean fragments. If complete removal is the goal, thorough excavation is necessary to ensure that no pieces of the water-storing tubers or spreading rhizomes are left in the soil. Any remaining small segments can sprout new plants, demanding persistence and close inspection of the soil to prevent reestablishment.