Wire grass, commonly known as Bermuda grass (Cynodon dactylon), is a warm-season grass that is a tenacious and invasive lawn weed. Its aggressive growth habit allows it to quickly colonize desirable turfgrass and garden beds. The challenge in eradication stems from its unique, dual root structure and its resilience to common removal attempts. Understanding the biology of this plant is the first step toward developing an effective, multi-pronged strategy to permanently clear it from a landscape.
Understanding the Aggressive Nature of Wire Grass
The difficulty in eliminating wire grass is directly tied to its sophisticated method of spread and survival. This grass utilizes two distinct types of creeping stems to establish and expand its territory. Above ground, it sends out stolons, which are horizontal runners that root at the nodes to form new plants, allowing rapid surface coverage.
Below the soil line, wire grass relies on rhizomes, which are underground stems that store energy and penetrate deep into the ground. These rhizomes serve as the plant’s primary survival structure, enabling it to endure drought, cold, and physical disturbance. Severing these stems through tilling or improper manual pulling only encourages fragmentation, where each small piece can regenerate into a new plant, multiplying the problem.
Non-Chemical Eradication Strategies
For areas where chemical treatments are undesirable, physical removal and environmental denial methods offer effective alternatives, though they require patience and thoroughness. Successful manual removal demands that the entire root system, including all underground rhizomes, is carefully dug out of the soil. Removing surrounding soil clumps is also necessary, as they often contain fragments of runners that can quickly re-establish themselves.
Solarization is a highly effective non-chemical method that utilizes the sun’s energy to superheat the soil. This process involves mowing the grass low, thoroughly wetting the area, and covering it with clear plastic sheeting for six to eight weeks during the hottest part of the year. The intense heat generated beneath the plastic aims to kill the rhizomes and stolons, though some deeply buried rhizomes may still survive.
Smothering, or sheet mulching, is a slower but equally effective technique that works by denying the grass access to sunlight. This involves laying down light-blocking materials, such as heavy layers of cardboard or thick black plastic, and covering them with a deep layer of mulch. This method must be maintained for several months to ensure the grass exhausts its stored energy reserves and prevents new shoots from emerging.
Selective Chemical Control for Established Lawns
In established lawns where wire grass is intermixed with desirable turf, targeted chemical control often provides the most efficient removal solution. Herbicides are categorized into selective and non-selective types, and the choice depends on whether the goal is to save the surrounding turf. Selective post-emergence herbicides are designed to suppress or eliminate wire grass without harming most cool-season turfgrasses, such as tall fescue.
Active ingredients like fenoxaprop, fluazifop, or topramezone are commonly used in selective treatments. These often require multiple applications spaced three to four weeks apart to deplete the plant’s underground energy stores. These chemicals are most effective when applied to actively growing wire grass, typically in late spring or summer when the plant is aggressively photosynthesizing. Following the product label instructions precisely is essential, as over-application can damage the surrounding desired turf.
For areas completely taken over by wire grass, or for complete renovation projects, non-selective herbicides are necessary. Glyphosate is the standard non-selective option, killing nearly all vegetation it contacts by translocating down into the root system to target the rhizomes. Multiple applications are usually needed. The first application should occur when the grass is actively growing, followed by an application on any regrowth before replanting the area.
Long-Term Maintenance to Prevent Reinfestation
After initial eradication, long-term maintenance practices are necessary to create an environment unfavorable to wire grass regrowth. One primary cultural control is raising the mowing height of the desirable turf, especially for cool-season grasses like tall fescue. Maintaining a taller canopy, often at four inches or more, shades the soil and reduces the sunlight available to the low-growing wire grass.
Adjusting irrigation practices can also significantly discourage reinfestation. Wire grass thrives on shallow, frequent watering. Switching to deep, infrequent watering encourages the desirable turf to develop deeper, more robust root systems, thereby out-competing the wire grass for resources.
Ensuring optimal soil health through regular aeration and fertilization helps maintain a dense, vigorous lawn that naturally resists weed invasion. A thick, healthy stand of turf provides a strong biological barrier, blocking wire grass stolons from establishing new roots and out-competing stray rhizome fragments.