Weeds vary in texture, color, and growth rate from the turf grass they invade, creating an undesirable appearance. Control weeds in Bermuda grass by hand-pulling weeds and by applying herbicides. Turf grass weeds are divided into two large classes of plant types: grassy weeds and broadleaf weeds. Weeds may be summer annuals, winter annuals or perennials. Follow instructions carefully in selecting a herbicide and applying the correct quantity to control Bermuda grass weeds.
Apply pre-emergent herbicides on Bermuda grass before greening. Pre-emergent herbicides prevent germinating weeds from establishing in the lawn. These herbicides control annual grassy weeds by inhibiting cell division in young root systems. Apply in early spring for cool season grasses and twice annually—in early spring and fall—for warm-season grasses. Commonly used pre-emergent herbicides include dithiopyr, pendimethalin, oryzalin, and isoxaben. Pre-emergent herbicides are granular products distributed with a spreader. Achieve the most effective coverage by making two perpendicular passes over the lawn, using one-half of the total amount of herbicide on each pass.
Apply post-emergent herbicides after weeds have erupted in the lawn, preferably when they are young and actively growing. Correct weed identification allows you to select the correct herbicide. Common weeds in turf grass that are treated with a post-emergent include dandelions, crabgrass, dallisgrass, bluegrass, henbit, and chickweed. Rutgers University extension has pictures of over 100 common lawn weeds to aid in identification (see Resources).
Select an herbicide that targets the type of weed you need to kill. The most common selective weed killer for post-emergent lawn weeds is 2,4-Dichlorophenoxyacetic acid (usually abbreviated as 2,4-D). Methylchlorophenoxypropionic acid, often listed on herbicide labels as MCPP, may be used alone or in combination with 2,4-D for weed control. Post-emergent herbicides containing 2,4-D, MCPP, dicamba, triclopyr, MCPA and dithiopyr are applied in liquid form for spot treatment or granular form to cover the entire yard. If applying as a liquid, spray only on days with no wind to minimize drift. Post-emergent weed-control herbicides may be used two to three times per year.
The best organic method of removing weeds from turf grass lawns is hand digging each weed. Corn gluten meal has shown some effectiveness as a pre-emergent herbicide. Corn gluten meal is a by-product of processing corn to make cornstarch and corn syrup. It is generally sold as a golden yellow meal or as light brown granules. According to the Environmental Protection Agency’s Office on Pesticides, corn gluten meal prevents sprouting seeds from developing normal roots, making them susceptible to dehydration. Corn gluten meal does not kill established weeds.