Henbit

Biology

Henbit (Lamium amplexicaule) is a winter annual broadleaf weed, commonly found throughout the United States. It germinates in fall and survives winter, flowering and producing seeds before dying in late spring or early summer. Henbit, part of the mint family, has a distinct four-sided stem and hairy leaves. The upper leaves deeply lobed and encircle the stem. Its flowers are small, pinkish-purple, and tubular. Control methods include cultural practices like proper mowing and fertilization, organic postemergence herbicides, and chemical treatments with products containing 2,4-D, dicamba, or triclopyr

Identification

Henbit, a common winter annual weed in the U.S., germinates in fall and dies in late spring or early summer. It’s identified by its square stem, hairy leaves, and small pinkish-purple flowers. Effective control methods include proper lawn maintenance, such as mowing and fertilization, and the use of specific herbicides.

Cultural control

Cultural practices that promote a dense, vigorous turf are the best way to reduce the encroachment of annual broadleaf weeds. For example, proper mowing (increased mowing heights), proper fertilization to improve turf density, irrigation to prevent drought stress, and aerification of compacted soils to improve root health are all cultural practices that can be used to manage henbit in turf. However, in situations where you only have a few plants, you can usually just pull henbit by hand.

Biological control

There are some organic postemergence herbicides available to control henbit. For example, pelargonic acid (Scythe) and acetic acid (5% or greater solutions) may be used to manage weeds. Other products such as Eugenol, which contain medium-length fatty acids and clove oil, have shown also some promise as an effective weed control tool. However, these organic herbicides do not differentiate between the target weed and the desired turf (non-selective) and should only be applied as spot treatments in direct contact with the weed only. As a result, most of these organic herbicides have limited use in turf and are better suited for weed control in parking lots, along fence rows, and in other bare-ground areas.

Many new organic products contain iron HEDTA (FeHEDTA) as the active ingredient. Multiple applications of these products are required for adequate weed control and turf injury is generally decreased (can actually make the turf darker); however, their ability to control weeds is not well-documented.

Chemical control

Henbit can be controlled by using both preemergence and postemergence herbicides. However, preemergence control is mostly utilized in bermudagrass and zoysiagrass lawns so chemical control discussions will focus predominantly on postemergence herbicides. Most postemergence herbicides that contain 2,4-D, dicamba, floroxypyr, triclopyr, and others will control henbit. The ideal time to make herbicide applications is when the plant is small in autumn. As the plant gets bigger, herbicides will become less effective at controlling henbit. Additionally, winter annuals will naturally die in the summer; therefore, late spring herbicide applications are generally not needed. When henbit leaves start to turn yellow in color, they are beginning to die naturally from heat stress and herbicide applications are no longer necessary.