Black Henbane

Black henbane is an annual or biennial forb inthe Solanaceae (nightshade) family. It grows from a taproot to form a basalrosette in its first year of growth; in the second year of growth it produces astem that usually reaches 3 feet and occasionally up to 6 feet tall. Leaves aregray-green in color with prominent, white mid-veins. Leaves are large and maybe between 2 and 8 inches long and up to 6 inches wide with toothed or lobedmargins. Leaves are covered in sticky hairs that exude a “fetid” odor. Blackhenbane produces distinct, showy flowers from mid spring to late summer.Flowers are produced on racemes and are large, reaching up to 2 inches across.They are funnel-shaped with 5 lobes at the top which are fused at the base.Outer parts of the flower may range from a pale cream to green tobrownish-yellow with purple veins while the center of the flowers arefrequently deep purple to black. Seeds are small and black, and they are formedin urn-shaped cups on the flower stem. Flower stems are somewhat woody and maypersist in the environment for several seasons after the rest of the plant hasdied.

Black henbane produces the tropane alkaloidshyoscyamine, scopolamine, and atropine in all parts of the plant. While blackhenbane has historic medicinal properties, these alkaloids can be fatally toxicto humans, livestock, and wildlife. Care should be taken when handling allparts of the plant as the alkaloids can be absorbed through the skin.

Black henbane is native to Eurasia and wasintentionally introduced to North America in the early 1600s for its medicinalproperties. It spreads solely by seeds. Seeds are dispersed by humans,wildlife, livestock, and water. In Teton County, black henbane is frequentlyfound in disturbed sites and new construction where dispersal likely occurredthrough contaminated equipment or materials. It is also found along roadsides,paddocks, and trails.

Prevention and cultural control strategiesshould be utilized as much as possible.

There are no biological control agentscurrently available for release in Teton County.

Because black henbane has a taproot, it can bereadily managed by hand pulling or digging out the root. Tilling or hoeing isalso effective for management when the taproot is severed 2 or more inchesbelow ground. Controlled grazing is not recommended due to potential forpoisoning. Mowing or chopping will not eradicate stands of black henbane, butit can be beneficial in preventing seed production. Do not mow while seeds arepresent.

Larger infestations can be controlled withherbicides. Spring and fall treatments of rosettes are recommended, buttreatment of bolting plants can be effective. Flowering plants may be choppedand remaining rosette and stem treated with herbicide to prevent reflowering.Read the label before using any herbicide. Contact TCWP if you have anyquestions about application rates or how to use an herbicide.

• Weed Report: Black Henbane from Weed Control in Natural Areas in the Western United States (2013) DiTomaso, Kyser et al. University of California.
• Black Henbane: Identification, Biology and Integrated Management (2017) Pokorny, M. et al. Montana State University Extension.
• Black Henbane. Range Plants of Utah. Utah State University.
• The Powerful Solanaceae: Henbane. United States Department of Agriculture Forest Service.