How do I Prevent St. Augustine Grass from Spreading?

Hand-pull St. Augustine in small patches before it can spread.

Select a commercial crabgrass killer that contains a warning that it will also kill St. Augustine grass. Examples of this type of grass killer include arsenates such as MSMA, MAMA, DSMA or CAMA. Although these warnings are to prevent you from using the products to kill weeds in a St. Augustine grass lawn, they mean that the chemical will effectively kill St. Augustine grass.

Wear protective clothing when treating a lawn with these chemicals, including breathing protection and gloves. Although most herbicides are supposed to be non-harmful to humans, you should still treat them as potentially harmful chemicals. You should also shower as soon as you have finished using the chemical.

Hold the spray bottle of herbicide away from yourself at arm's length. The nozzle of the spray bottle should be between 12 and 24 inches away from the top of St. Augustine grass. Spray the herbicide until the portion of grass you want to eliminate and keep from spreading is saturated.

Wait up to two weeks before re-treating any St. Augustine grass that has not been killed.