Lamium amplexicaule is a cool-season annual weed 10-40 cm tall. Its stems are thin, pubescent, and greenish purple in colour.
It can be easily identified by its showy 2-lipped tubular pink to purple flowers which are a big attraction for hummingbirds and honey bees.
Lamium amplexicaule Classification
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Lamiales
- Family: Lamiaceae
- Genus: Lamium
- Species: Lamium amplexicaule
- Common Names: Henbit, Greater Henbit, Common deadnettle, Bee nettle, and Deadnettle
Nativity and Distribution
Henbit deadnettle is native to Europe, Asia, and North Africa. It is also found in:
- North America
- Central America
- South Africa
- Tasmania
- Australia
- South America
Physical Characteristics
- Leaves: Opposite, round to kidney-shaped with a lobed margin
- Fruits: Oblong, 1-2mm long, brown nutlets
- Stems: Herbaceous. It can grow up to 10-40 cm tall
- Flowers: Showy pink to purple 2-lipped flowers
- Roots: Shallow fibrous root system
Lamium amplexicaule is a cool season annual that grows up to 10-40 cm tall. It is easily recognized by its vibrant hairy pink to purple flowers whorled around the stems.
Stems are square in cross-section (quadrangular), softly haired, and green with hints of purple in colour. They can be upright but can also trail along the ground.
Henbit has two leaf arrangements but are generally oppositely arranged, slightly pubescent, and mostly green with purplish hues, especially in younger plants.
The lower leaves are stalked with petioles up to 6 cm long. They are round to heart-shaped, with a crenate margin about 1-2 cm wide and 1-2 cm long. The upper leaves are 1-3 cm wide and 2-4 cm long, sessile, fused, deeply lobed, and clasping to the stem, hence the name, “amplexicaule”.
L. amplexicaule produces showy pink to purple flowers fused into a 2-lipped tube, 1-1.5 cm long. They are located in the leaf axils of the upper leaves with 6-10 flowers in a single whole. Flowering starts in April and lasts for 1-2 months.
The seeds are brown with white spots, oval, about 1.5-2 cm long.
Reproduction, Dispersal, and Life Cycle
- Life Cycle: Annual
- Seeds: Can produce 40-200 seeds
- Climate: Temperate climate with moderate temperatures and precipitation
- Dispersal: Wind, water, and animals.
Lamium amplexicaule behaves as an annual and reproduces by seed. A single plant can produce 40-2000 seeds which are generally viable.
Seeds germinate on the soil surface or in shallow soil (to a depth of 2.5 -6 cm). The seeds beneath this depth can remain viable for at least 5 years.
Wind and animals disperse the seeds over short distances. Water, particularly floods, birds, and contaminated agricultural machinery can also disperse the seeds over long distances.
Similar Plants
- Lamium purpureum
- Lamium maculatum
- Glechoma hederacea
- Veronica persica
Uses
- Young leaves can be cooked as vegetables or added to salads.
- It is grown as an ornamental and pollinator plant.
- It is used as a traditional medicine to treat coughs.
- It is used as ground cover to prevent soil erosion.
Impact on Farms and Environment
Henbit deadnettle is highly competitive for important resources, negatively impacting agricultural winter crops like barley, corn, and sorghum.
While it may be good forage for livestock, it can cause mild neurological problems (staggers) in cattle, sheep, and horses if consumed in large quantities.
Henbit is a weed of open areas, pastures, gardens, landscapes, and uncultivated areas, and can outcompete native vegetation, negatively impacting biodiversity.
As a pollinator plant, it provides food for various insects and a habitat for beneficial organisms. However, it can also host destructive pests like corn earworm and soybean cyst nematode, and overwinter the spotted spider mite which can threaten crop growth.
Control
- Mechanical control: Hoeing, hand-pulling, and cultivation
- Chemical control: Herbicides like Glyphosate, Paraquat, 2,4-D, Dicamba, and Aminopyralid.
Intensive tillage in summer crops will help limit the growing foliage and can help manage large infestations over time. Similarly, for small infestations, hoeing and hand pulling in gardens and landscapes can provide effective control against henbit deadnettle.
Chemical control depends on the crop system. Refer to your local treatment regimens, online resources, and local experts to get the right information for your crop. When using any herbicide always read the label first and follow all the manufacturer’s instructions.
No biological control agents have been developed against L. amplexicaule.
Lead Editor for Insight Weeds.