Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Henbit

Table of Contents

1. Scientific name
2. Other names
3. Family
4. General Description
5. Habitat
6. Seedlings
7. Stems
8. Leaves
9. Flowers and Fruit
10. Often confused with/Distinguishing features
11. References
12. Related Links

Scientific name:

• Lamium amplexicaule L.,

Other Names:

• lamier amplexicaule, pain de poule

Family:

• Mint Family (Labiatae)

General Description:

• Henbit is an annual or winter annual reproducing only by seed.

Habitat:

• Henbit is found throughout southern Ontario in gardens, waste areas and along roadsides.

Seedlings:

• The cotyledons are oval and range in length from 3 to 12 mm
• Hypocotyl starts green and turns purple as it matures
• The base of the cotyledon is notched, giving the leaves a heart shape appearance

• Stems are square and erect
• Finely hairy
• Reach a height between 10 and 40 cm
• Very branched near the base with branches that spread, then become erect

• Leaves are opposite (2 per node)
• Young leaves occur on the petioles and have a crinkled upper surface
• Lower leaves are long-stalked, broad, somewhat heart-shaped and have coarsely lobed or irregularly toothed margins
• Upper leaves are stalkless, have a broad-base and clasp the stem
• The upper leaf surface as well as the veins on the lower leaf surface have hairs

• Flowers are found in clusters (whorls) in the leaf axils of the upper leaves
• The calyx of the flower is small, tubular, ribbed with 5 small, sharp teeth
• The corolla of the flower is pink or purple, 12-18 mm long and made up of 5 united petals
• Flowers in spring and early summer and sometimes in late summer and autumn.
• The fruit are small, egg-shaped nutlets that are approximately 2 mm long, brown with white spots

Often confused with/Distinguishing Features:

• Henbit is often confused with purple or red deadnettle. Unlike, henbit, purple deadnettle's upper leaves are triangular and are red or purple tinted. Henbit is distinguished from other weeds by its erect branching, square stems and opposite leaves. The distinguishing leaves are the upper leaves that clasp the stem. The clusters of pink or purple flowers in the leaf axils are also notable.

References

http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/henbit.htm

http://www.weedinfo.ca/en/weed-index/view/id/LAMAM

Photos

Figure 1: Henbit seedling at the 2-leaf stage

Figure 2: Henbit stem with 2 opposite leaves that clasp the stem giving a "whorl-like" appearance

Figure 3: Henbit stem axils with clustered purple flowers

Figure 4: Henbit flower

Related Links

... on general Weed topics
... on weed identification, order OMAF and MRA Publication 505: Ontario Weeds
... on weed control, order OMAF and MRA Publication 75: Guide To Weed Control

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