A sure sign that spring is here are the lawns that suddenly turn purple with an explosion of purple flowers in their lawn. This weed is a winter annual weed named Henbit, a member of the mint family. If you rub it in your fingers, you’ll notice the stems are square and with a minty smell to it. These weeds, along with chickweed, annual bluegrass and others, germinate in the fall, but really don’t show themselves much until the first warm days of early spring. Left unchecked, like all weeds, they can choke out healthy turf and look bad in the process.
The best means of control for henbit and other winter annual weeds is to apply a pre-emergent in the fall, which nips them in the bud before they even germinate. Without this, these weeds can take over a lawn. At this time of the season, if a lawn has been properly treated in the fall, bermudagrass and zoysiagrass should be clean, brown, and dormant still. Fescue lawns are starting to green up a little with warmer weather, and being green, tend to mask the weeds somewhat. But they are still there. At this point, the best means of control is the application of a liquid post-emergent herbicide such as Trimec, which is what we use at LawnAmerica. It’s safe to use as long as label instructions are followed and applied at the proper rates. It will take time though for the henbit to totally die out. If you mow down the dying weeds about 5 days or so after treating, that will speed up the weed’s dying, and you’ll be removing much of the dead vegetation so that you lawn will look nicer. We aren’t using some type of magic juice that makes the weeds just disappear after they are sprayed. Mother Nature has to slowly allow them to die and then decompose into the soil, and that takes time.
So while one can spray henbit and other early spring weeds, preventing them in the first place is much better. By maintaining a thick, healthy turf and applying timely fall pre-emergents this season, your lawn won’t be invaded by these purple monsters next spring.