Eliminating a broadleaf weed like Henbit (Lamium amplexicaule) while preserving turfgrass is a common challenge for homeowners. Henbit is a widespread weed that invades thin or stressed lawns, often becoming noticeable in cooler months. Selective control methods must target the weed’s unique biology without causing damage to surrounding grass species like fescue, bluegrass, or Bermuda. Effective management requires understanding the weed’s life cycle and applying chemical and cultural techniques precisely.
Identifying the Target: Henbit’s Life Cycle
Henbit is classified as a winter annual, which is a significant detail for effective control planning. Its seeds typically germinate in the late summer or fall, establishing small plants that survive the winter as a low-lying rosette of leaves. This life cycle means the weed is actively growing during the dormant or semi-dormant period of many common turfgrasses.
The plant resumes vigorous growth in the early spring, quickly producing its characteristic pink to purple flowers and setting seed. As temperatures rise in late spring and early summer, the Henbit plant completes its life cycle and dies. Control efforts must focus on treating vulnerable seedlings in the fall or actively growing plants in the early spring before they produce seeds that fuel future infestations.
Selective Chemical Control Options
Controlling Henbit without harming turfgrass relies on selective, post-emergent broadleaf herbicides. These products target the growth mechanisms specific to dicots (broadleaf plants) while leaving monocots (grasses) unharmed. The most effective herbicides are often sold as “three-way” mixes that combine active ingredients like 2,4-D, MCPP (Mecoprop), and Dicamba.
These synthetic auxin herbicides mimic plant hormones, causing uncontrolled and lethal growth in Henbit. Application is most effective in the fall or early spring when the weed is small and actively growing, before it reaches the flowering and seeding stage. For warm-season turfgrasses like St. Augustine or Centipede, alternative selective herbicides, such as those containing Atrazine or Metsulfuron, may be recommended to avoid turf injury.
For proactive control, pre-emergent herbicides prevent weed seeds from germinating. Products containing active ingredients like Prodiamine, Pendimethalin, or Dithiopyr are effective. Application timing is crucial and should occur in the late summer or early fall, before Henbit seeds begin to sprout. Always consult the product label to confirm the correct application rate and safety for your specific turfgrass species.
Non-Chemical and Cultural Prevention
While chemical treatments provide rapid elimination, long-term Henbit management relies on cultural practices that promote a dense, healthy lawn. A thick turf minimizes open soil areas where Henbit seeds can germinate. Simple mechanical removal is an option for minor infestations, especially when the soil is moist, since Henbit has a shallow root system.
Adjusting mowing, fertilization, and irrigation schedules reduces the likelihood of Henbit establishment. Mowing at the highest recommended height encourages a denser canopy, which shades the soil and prevents weed seed germination. Proper fertilization ensures the grass is vigorous enough to outcompete Henbit. Deep, infrequent watering is preferable to light, frequent watering, as the latter keeps the soil surface moist, favoring Henbit seed sprouting.