Henbit, Henbit Deadnettle, Giraffe Head
General: Common Dead-Nettle is a winter annual in the Mint family.
Flowers: The flowers are small and orchid-like. The Common Dead-Nettle flowers are typically purple, sometimes pink. They grow in clusters at the axils of the broad, stalkless upper leaves.
Stem: The erect Common Dead-Nettle stems are square and slender with fine hairs covering the length of the stem. Common Dead-Nettle can grow 10 – 40 cm tall and is highly branched near the base of the plant. When the plant is young it initially grows outward before maturing and becoming erect.
Leaves: The Common Dead-Nettle are rounded and either egg- or heart-shaped with coarsely blunt-toothed margins. The leaves are typically 1 – 2 cm long and 1 – 3 cm wide. The lower leaves have long stalks, whereas the upper leaves are stalkless, broad-based, and can be clasping at the stem. Common Dead-Nettle leaves are hairy on the upper surface.
Fruit: Common Dead-Nettle forms nutlets of four seeds clustered together. The seeds are brown with white spots and are triangular with squared-off tips.
Roots: Common Dead-Nettle has a shallow taproot.
Habitat and Origin
Common Dead-Nettle is native to Eurasia but has since spread across the world.
Common Dead-Nettle prefers mesic to dry conditions in disturbed areas. It typically grows by roadsides, in croplands, pastures, waste areas, gardens, and on lawns. It thrives in light, dry, cultivated soil, and does not tolerate shade.
Propagation & Vectors of Spread
Common Dead-Nettle reproduces solely by seed. Plants contain both male and female flowers, so they can self-pollinate with the help of bees.
Common Dead-Nettle seeds are dispersed over short distances (under 10 m) by wind and animals. Seeds travel further in flooding events, or when birds and other animals consume the seeds. It is also spread through the horticultural trade, as seeds can be purchased for use in wildflower gardens.
Ecological, Economic, & Health Impacts
- Outcompetes herbaceous vegetation, especially in turf grasses and landscapes.
- Threatens biodiversity.
- Hosts a range of plant pests that can affect agriculture or ornamental crops, such as Beet mild yellowing virus, Potato virus Y, Strawberry latent ringspot virus, and Tomato spotted wilt virus.
- Unsightly in turf and lawn areas.
What Can I Do?
Common Dead-Nettle is NOT currently found throughout the Sea to Sky Corridor, so the best approach to controlling its spread is by PREVENTION.
Learn to identify Common Dead-Nettle: use the images presented in this profile page to learn how to identify Common Dead-Nettle.
What to do if you spot it: You can report any Common Dead-Nettle sighting by clicking here.
- Regularly monitor properties for weed infestations.
- Ensure soil and gravel are uncontaminated before transport.
- Check wildflower mixes to ensure that they do not contain Common Dead-Nettle.
- Ensure that plants are disposed of in a garbage bag if found in floral arrangements to prevent seeds from spreading.
- Don’t unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles, or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
- Don’t plant Common Dead-Nettle in a garden, no matter how well-contained its enclosure may seem.
- Don’t move soil that has been contaminated with Common Dead-Nettle.
- Do not compost any Common Dead-Nettle plant parts.
Tillage or cultivation is an effective way to control the seedlings. Small infestations can be hoed or pulled by hand.
Numerous herbicides are effective at controlling Common Dead-Nettle, including aminopyralid, dicamba, glyphosate, imazapyr, metsulfuron methyl, and rimsulfuron. We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.
Although Common Dead-Nettle is a host to a number of crop pests, none is an accepted biocontrol agent for this plant.
- CABI, Henbit Deadnettle, https://www.cabi.org/isc/datasheet/29728
- Edible Wild Food, Henbit, https://www.ediblewildfood.com/henbit.aspx
- Electronic Atlas of the Flora of BC, Common Dead-Nettle, http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Lamium%20amplexicaule
- Ontario Ministry of Agriculture Food and Rural Affairs, Henbit, http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/henbit.htm
- Farmers Business Network, Where Did These Weeds Come From?, https://emergence.fbn.com/agronomy/where-did-all-of-these-weeds-come-from
- Ontario Weed Committee, Henbit, http://www.weedinfo.ca/en/weed-index/view/id/LAMAM
- Plants for a Future, Lamium amplexicaule – L., https://pfaf.org/User/Plant.aspx?LatinName=Lamium+amplexicaule
- UC Davis, Henbit, https://wric.ucdavis.edu/information/natural%20areas/wr_L/Lamium.pdf
- US Department of Agriculture, Henbit deadnettle, https://plants.usda.gov/core/profile?symbol=LAAM