Black Henbane
Hyoscyamus niger
Washington State Classification
Class C — Widespread, County-Selected Control
Black henbane is a cultivated ornamental plant and that has spread throughout the United States.
Quick Reference
Identification
Growth Habit
It is an annual or biennial plant that grows up to about 3 feet tall and is covered in glandular hairs, making the plant sticky.
Leaves
Leaves are coarsely-toothed to shallowly lobed. They are sticky and hairy with a foul odor. Leaves may grow in rosettes (a radiating cluster of leaves at ground level) the first year.
Flowers
Flowers bloom from May to August and are in one-sided clusters (racemes). Flowers are funnel-shaped with the petals fused at the based and 5 lobed at the tips. They are greenish to brownish-yellow with a purple center and purple veins
Fruit & Seeds
Seeds are in small (1 mm), with many in each capsule.
Impact
Black henbane is a cultivated ornamental plant and that has spread throughout the United States. It contains hyoscyamine and other alkaloids which have been known to cause occasional livestock poisoning. It is also considered a poisonous plant to humans.
Ecology & Spread
Habitat
Black henbane can be found growing in pastures, fence rows, roadsides, and waste areas. Please click here to see a county level distribution map of black henbane in Washington.
Spread Mechanisms
Reproduction
Black henbane reproduces by seed. Seeds germinate easily and will remain viable in the soil for several years.
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Control Methods
Mechanical
- Hand-pulling or digging can be effective if the taproot is entirely removed. In order to prevent seed dispersal, plants with mature fruits should be put in bags after removal. The area must be monitored for new seedlings for at least four years. Mechanical control methods are only effective for small infestations. Wear gloves and protective clothing when handling the plants to prevent rashes.