Zoysia grass is a popular warm-season turf grown across the transition zone and southern climates due to its dense, carpet-like growth habit and resilience. It is highly valued for creating a luxurious lawn texture that is comfortable underfoot and durable against heavy use. Zoysia does have runners, as it relies entirely on these specialized stems for its lateral spread. Its method of growth gives it both its desirable qualities and its challenging maintenance requirements.
Understanding Zoysia’s Spreading Mechanism
Zoysia grass utilizes a powerful dual system of horizontal stems, commonly called runners, to propagate and thicken its turf. These runners are classified as both stolons and rhizomes, a combination that makes the grass aggressive in its growth. Stolons are above-ground stems that creep along the soil surface, rooting at their nodes to produce new individual plants or tillers.
Rhizomes, in contrast, are the below-ground runners that spread horizontally beneath the soil surface. These underground stems store energy and send up new shoots, allowing the plant to colonize new areas from below. Zoysia’s use of both stolons and rhizomes results in a highly interconnected, mat-like root structure. This dense lateral expansion is why Zoysia establishes a lawn that is so thick and competitive against weeds.
The Impact of Lateral Growth on Turf Quality
The extensive network of runners is directly responsible for the superior density that Zoysia lawns are known for, which gives the turf a desirable “cushiony” feel. As the stolons and rhizomes continually send up new shoots, the grass blades grow closely together, creating a thick barrier. This high shoot density is also why established Zoysia turf is so effective at suppressing weeds, as the dense canopy blocks sunlight from reaching the soil.
The interconnected root and stem structure also contributes to the grass’s high tolerance for foot traffic and wear. The lateral growth means that if a portion of the lawn is damaged, the runners can quickly fill in the bare spot, aiding in recovery.
The Thatch Problem
However, this rapid lateral growth is a drawback because the runners are composed of tough, fibrous material that does not decompose quickly. This leads to the major drawback of Zoysia: excessive thatch development. Thatch is the tight layer of living and dead stems found between the soil surface and the green grass blades. When thatch exceeds half an inch, it can impair water and nutrient absorption.
Controlling Zoysia’s Aggressive Spread
Because Zoysia’s runners are so aggressive, homeowners need to proactively manage its spread to prevent it from invading flower beds, sidewalks, or neighboring lawns. The most effective method for containment involves the installation of physical barriers. To stop both the above-ground stolons and the underground rhizomes, edging material must be placed into the soil at least six inches deep.
Leaving two to three inches of the barrier above the soil surface prevents the stolons from creeping over the top. Due to the rapid accumulation of thatch caused by the dense runners, Zoysia also benefits from regular maintenance such as vertical mowing or dethatching. This process removes the excessive organic layer, helping to ensure the lawn remains healthy and able to absorb water and air efficiently.