Dealing with Invasive Wild Bermudagrass (Wiregrass) in a St. Augustine Lawn

The Wiregrass Challenge

A homeowner discovers “wild bermudagrass” (Cynodon dactylon, aka wiregrass or devilgrass) invading their St. Augustine lawn. Sugar applications have improved the lawn overall, but the wiregrass persists.

Reality Check

Wiregrass is exceptionally aggressive: it spreads by rhizomes, stolons, and millions of seeds per kilogram. It can grow through asphalt. Conventional eradication requires repeated glyphosate applications or summer soil solarization—both difficult for organic gardeners.

Management Options

• Accept some coexistence; wiregrass thrives in rich soil just like desirable turf.
• Solarize the affected area in summer (clear plastic for 4–6 weeks) to kill seeds and roots.
• Spot‑treat with a selective herbicide like fluazifop (Fusilade II) if organic methods fail, but note it may harm other grasses and soil life.
• Maintain dense St. Augustine through proper mowing (3″), deep watering, and organic feeding to maximize competition.

Complete eradication is rare; ongoing management is the practical goal.