A well-kept zoysia lawn provides a thick, dense ground cover that crowds out most weeds and deprives new growth of life-giving sunlight. Lawn care neglect and cutting the grass too short, however, will give crabgrass a foothold in your lawn, which it will take advantage of unless you remove it immediately. Although crab grass is an "annual" plant that dies naturally at the end of its season, it will seed itself for a vigorous return in the spring.
Things You'll Need
Maintain your zoysia lawn according to its needs in your particular climate. In southern regions where rainfall may be less than average and your lawn can be stressed by heat and sun evaporation, you must water more frequently. Feed your zoysia lawn with zoysia-specific fertilizers in spring, summer and fall to ensure a dense growth that will crowd out all weeds including the shallow-rooted crab grass. Immediately reseed bare areas to deny crab grass a foothold to grow in.
Mow your lawn to maintain 2 1/2 to 3 inches of length. The taller grass will shade the ground and will prevent crab grass from sprouting. Keep your lawnmower blade sharpened to prevent it from pulling out zoysia plants and thereby offering bare spots for crab grass to grow in.
Remove individual clumps of crab grass as you find them. Soak the soil around the crab grass with enough water to soften the ground and to loosen the weed's shallow roots. Pull individual crab grass clumps out with your hands or with the assistance of a knife or a weed puller if they resist.
Apply a recommended herbicide when your zoysia lawn has been overtaken by crab grass. Once it has taken hold of your lawn it will quickly spread. Pulling out individual plants may then become too tedious and a chemical application is warranted. Apply according to directions on the package.
Carefully spread a recommended herbicide on your zoysia lawn in the very early spring. Seeds that will have been sown by the parent plants in the previous season will otherwise emerge in record numbers.
When using commercial herbicides read the label carefully and apply the chemical according to the instructions. These products kill a wide variety of plants and misuse can quickly destroy an entire lawn. Increasing a recommended dose, for instance, may prove to be more dangerous to your lawn than beneficial.