No one likes to see weeds in their pristine zoysia grass seed lawn. Why do they occur, and how do you get rid of them?

First, it’s important to realize that any plant can be classified as weed if it is unwelcome in a certain environment. Your idea of what a weed is could change over time. Second, a weed will only have the opportunity to grow if there is space for it to grow in—i.e., a thinning zoysiagrass lawn is a welcome opportunity for any weed growth. A thin lawn can be caused by a number of factors: you might be mowing the lawn too closely, over or under watering, over or under fertilizing, trying to grow zoysiagrass in overly shady conditions, or growing the lawn on a compacted layer of soil or a soil with an unbalanced pH level. Before you try to remove the weed, identify what encouraged the weed in the first place. Otherwise you will be fighting a never-ending battle of removing new weeds. Properly identifying the weed can be a huge help in determining which characteristic of your lawn you should target. Clover, for example, thrives in soils with low nitrogen levels, which should be a signal to you that you should fertilize more often.

Once you have identified your weed and attempted to lessen its presence through cultural control, you can try to remove the remaining weeds by hand. Weeding is certainly not a chore that anyone wants to do, but it is better than using toxic herbicides every time you see a weed. Pull at plants carefully and make sure that you pull up any roots along with the plant, so that no regeneration occurs. Pull weeds when they are immature and before they have a chance to flower or seed. If you suspect that the weeds have already released seeds, bag your grass clippings for a few weeks and wash your mower blades well after mowing an infested area. That way you will lessen the chance of seeds spreading.

If the weeds are too numerous to control by hand pulling, you may use postemergence herbicides to control them. Postemergence herbicides come in two categories: selective and nonselective. Selective herbicides target specific plants, while nonselective herbicides will kill any plant and should be used in spot treatments only (e.g. glysophate). Pick an herbicide that is targeted for your weed and safe to use on your zoysiagrass lawn. Steer clear of weed-and-feed products. They might save time, but they will not provide your lawn the specific treatment that it needs.

Some weeds appear year after year and are usually known as summer annual or winter annual weeds. If you have a yearly problem with a certain kind of weed in your lawn, you may apply a preemergence herbicide to the soil before the weed even germinates. Preemergence herbicides create a barrier in the soil that blocks cell division in germinating seeds. Take note that preemergence herbicides will affect all seeds, so you shouldn’t try to plant any new zoysiagrass seeds after applying a preemergence herbicide. Depending on the length of the season, you may have to make multiple preemergence applications. They tend to break down every six weeks or so.

By implementing an integrated weed control program in your lawn, you will be able to manage weeds effectively and with the least amount of harm to the environment.