Bermuda grass (Cynodon dactylon) is an aggressive, warm-season perennial grass often considered an invasive weed when it infiltrates cool-season turfgrasses. Its resilience stems from its two-pronged growth strategy: above-ground runners (stolons) and below-ground stems (rhizomes). These creeping structures allow it to spread rapidly and store large energy reserves. Eradication is difficult because even small, severed fragments of rhizomes can regenerate into new plants, meaning a single treatment is rarely successful. Its presence is noticeable in cool-season lawns, as Bermuda grass turns brown when dormant after the first frost, disrupting the uniform green turf.
Preparation and Optimal Timing
The success of any removal effort hinges on proper timing and preparation to maximize the grass’s vulnerability. Bermuda grass is a warm-season plant, and its energy reserves are actively depleted during its peak growth period in the summer. Therefore, removal is most effective during the hottest part of the summer, typically between June and September, when the plant is drawing heavily on its root system.
Before treatment, the area should be “scalped,” or mowed extremely low, to remove as much leaf material as possible. This low cut exposes the stolons and reduces the plant’s ability to photosynthesize, forcing it to draw on stored rhizome energy. It is also beneficial to reduce water stress slightly, as a healthy, actively growing plant will more readily translocate applied herbicides down to its roots.
Non-Chemical Removal Methods
Three main non-chemical methods offer effective eradication, though they require patience and effort. Manual removal involves digging up the grass, which is an exhaustive process because rhizomes can penetrate the soil to depths of 6 inches or more. Every piece of rhizome and stolon must be removed, as any small fragment left behind can quickly sprout a new plant.
A less labor-intensive, though slower, technique is soil solarization, which uses the sun’s heat to sterilize the soil. This is achieved by cutting the grass low, watering the area, and covering it with clear plastic sheeting for four to eight weeks during the hottest months. The plastic edges must be completely sealed by burying them in soil to trap solar heat and moisture, raising the soil temperature high enough to kill the grass and its seeds.
Smothering, or occultation, is an organic approach that works by blocking sunlight entirely, forcing the plant to exhaust its energy reserves. This technique involves covering the area with thick, opaque materials like black plastic, cardboard, or heavy layers of organic mulch for several months. Using biodegradable materials like cardboard is advantageous because they can be left in place to decompose, adding organic matter to the soil structure once the grass is dead.
Targeted Chemical Control
When non-chemical methods prove insufficient, chemical control often becomes necessary for eradication. The preferred choice is a non-selective, systemic herbicide, such as glyphosate, which is absorbed by the leaves and transported down to the rhizomes and roots. Since Bermuda grass is resilient, a single application is usually only moderately effective, eliminating approximately 75% of the growth.
A successful treatment requires multiple applications to kill subsequent flushes of growth from surviving rhizomes. Apply the herbicide, wait until the grass shows signs of regrowth (typically 10 to 14 days later), and then apply a second treatment. For severe infestations, a third application may be necessary to achieve a high eradication rate, making it a process that spans several weeks. Safety precautions are necessary, and you must follow the product label’s instructions for personal protective equipment and the waiting period before re-seeding the area.
Restoration and Preventing Recurrence
Once the Bermuda grass is dead, the process of restoration can begin. After using a glyphosate product, it is possible to re-seed the area within a few days because the herbicide typically breaks down rapidly upon contact with the soil. The dead plant matter should first be raked out, and the soil should be prepared by core aeration to relieve compaction and improve oxygen flow.
Incorporating soil amendments like compost will help improve the soil structure and nutrient content before seeding the desired turfgrass. After seeding, maintain consistent moisture in the top layer of soil for the first two to three weeks to encourage germination and establishment. Long-term prevention involves installing physical barriers, such as deep edging or landscape borders, to stop new stolons and rhizomes from creeping in. Consistent monitoring and quick removal of any new sprouts are necessary to ensure the aggressive grass does not re-establish itself.