The growing season, albeit early, seems to be kicking into gear already. The trees are beginning to leaf out, flowers are beginning to bloom, and of course, the weeds are trying to get a head start on your lawn. One of the most common questions I get every year, is what is the weed with the purple flowers, and how do I get rid of it? Well, the weed most likely is called henbit, and I have some bad news for you. You can’t really eliminate it in the spring.
Henbit is a winter annual plant. This means that the plant first emerges in the fall, may grow slowly over the winter unnoticed, and then grow very quickly in the spring. The plant matures in the spring, produces seed, and then dies when the weather gets hot. With their biology, trying to control them now would both be frustrating, and most likely a waste of money. It is usually best to mow them regularly, fertilize in May (for cool-season grasses) to help your grass gain hold, and treat in the fall when they are small and vulnerable to chemical treatments.
The difficult part about this treatment option is to remember to treat your lawn for winter annuals in the fall and when you do remember, the best time to treat is in October. When looking for a weed control product, search for a label that specifies controlling Henbit, especially one that has  the chemicals 2-4D, MCPP and Dicamba together in a product as they have been found to give good control. No matter what control method you decide to use, be prepared to spot treat the next spring. By planning ahead, you can finally remove the purple flowers from your lawn.
Alicia Boor is the Agriculture and Natural Resources agent for Barton County K-state Research and Extension. One can contact her by email at aboor@ksu.edu or calling 620-793-1910