Henbit and Purple Deadnettle
You may be starting to see plants with small pink/purple flowers beginning to blossom in lawns and flower beds. Henbit, Lamium amplexicaule, is a winter annual from Eurasia and North Africa. As a member of the Mint Family, it has squares stems – a good identification characteristic along with it early spring flowers.
Henbit begins growth in the fall from seed, each plant producing as many as 2,000 seeds. It is seldom noticed when it first sprouts and not much attention is paid to it until it begins to bloom in the spring. And, by the time you notice it, killing it with an herbicide is usually a waste of money as it will rarely be killed. Weeding is a good control measure at this time of year, particularly so if you get them early before they go to seed. They pull up readily from a moist spring soil so the process is not too tedious. Preventing them from going to seed will greatly reduce the number of plants next year. As far as this year’s plants go, they mature in the spring and die off once it begins to get hot.
If you want to go the herbicide route you need to be observant in the fall when they germinate. Henbit generally germinates in October so spraying with a broadleaf herbicide on a warm day in November or early December can provide good control of the tender, young plants. Be very cautious though, the broadleaf herbicide you are using will just as readily do harm to your prized herbaceous perennials.
Another way to approach these plants is to view them as colorful garden additions and encourage them in areas that might not otherwise have flowers at this time of year. Remember, a weed is really just a “plant out of place”. And you get to decide what is the right place and what is not.
Purple deadnettle, Lamium purpureum, is also a winter annual that is in the Mint Family and can be confused with henbit. However, the deadnettle has more triangular leaves clustered near the ends of the purplish stems. In general it is a coarser appearing plants. Growth habit and control of purple deadnettle are similar to henbit.
Henbit photos from VA Tech, seedling, and Wikipedia, blossom.