Weeds in a Centipede Lawn

A warm season grass, centipede grass (Eremochloa ophiuroides) produces a coarse, low-textured grass that tolerates moderate shade. It will not withstand full shade or heavy foot traffic. A popular turf in the southern United States. The grass does require regular maintenance and weed control, especially during the winter months when centipede grass goes through a state of semi dormancy which can allow weeds to become prolific.

Weed Types

Weed control is an ongoing, yearlong process when growing centipede grass as a lawn. Annual weeds such as crabgrass, goosegrass,lespedeza, knotweed and spurge begin to appear in the spring months if control is not gained. As summertime weather emerges the spurge, knotweed, crabgrass and goosegrass become more vigorous. During the winter months chickweed and henbit easily overtake the semi dormant centipede grass. The weeds can appear quite striking if the centipede grass begins to turn brown during the cold weather but the weeds remain green.

Maintenance

Maintaining centipede grass in a healthy state can help reduce the weed growth. The grass benefits from applications of nitrogen to establish its root system and maintain its green color. Most centipede lawns require 1 to 2 lbs. of nitrogen per year, according to the Clemson University. Avoid fertilizing with phosphorus because centipede grass does not tolerate high levels well. The grasses overall health will be effected if there is an abundance of phosphorus in the soil which can weaken it so that weeds become more abundant. The grass often benefits from iron applications.

Weather Effects

Winter time freezes can have a detrimental effect on centipede lawns. The grass does not tolerate frost well because it only ever enters a semi dormant state so when the grass freezes and than warms up the grass is easily damaged. Several cycles of freezing and warming during the winter can easily kill large areas of centipede grass, according to the Texas A & M University. The areas of winter kill become highly susceptible to weed invasion.

Prevention/Solution

In the early spring the centipede grass will benefit from applications of preemergence herbicides to help prevent weed growth. Applications of postemergence herbicides in May will help control broadleaf weeds. The herbicide Vantage T&O (sethoxydim) will help prevent grassy weeds from occurring in the summer months. Broadleaf herbicides can be applied in the winter months. Products containing atrazine or simazine help to control annual broadleaf weeds from occurring in the winter months.

Warning

Care should be taken when using herbicides with a base of 2,4-D because centipede grass is highly sensitive to the chemicals, according to the Clemson University. Always follow the directions on the label when applying such herbicides and try to limit their usage to avoid damage to the grass. Herbicides containing metribuzin, pronamide, asulam, quinclorac, CMA, DSMA, MSMA and diclofop have also been shown to cause harm to centipede grass, according to the North Carolina State University.