Black Henbane: Eliminate This Unwanted Guest
Tuesday, July 15, 2025
Have you come across the infamous black henbane? It’s easy to spot with its tough stalks that can grow up to a meter tall and its vile smell, which earns it the nickname stinking nightshade. Its unsightly pale-yellow flowers with dark purple veins only add to its alarming appearance, making it stand out in fields, roadsides, and disturbed areas. Black henbane is designated as a noxious weed under the Weed Control Act in Alberta, meaning landowners are legally required to control its spread.
Historically, black henbane was associated with witches and used in a variety of supposed cures such as a remedy for insomnia. However, this plant is toxic to both humans and animals when ingested, and the severity of poisoning depends on the amount consumed. Symptoms can range from impaired vision and hallucinations to seizures, coma, and, in rare cases, death. Unlike many toxic plants, henbane retains its toxicity even when dried. While animals typically avoid grazing it due to its foul taste and odor, they may still consume it when mixed into hay or feed, leading to accidental poisoning.
Black henbane spreads aggressively primarily through its seeds, allowing it to establish a stronghold on your land. Each plant can produce up to 500,000 seeds, contained in distinctive, urn-shaped pods that burst open when mature, scattering seeds across the soil. These small, dark seeds can remain viable for up to five years, waiting for the perfect conditions to sprout and take over.
Prevention & Control
Preventing an invasion is the most effective way to control this troublesome plant. Black henbane’s biggest weakness is that it is a poor competitor. After disturbing the soil, be sure to reseed it as quickly as possible to choke out invasions. This persistent species requires early detection and prompt removal to halt its spread. Stay vigilant for potential habitats and infestations, and act swiftly to remove any new plants you spot.
Though black henbane is a tough opponent, several control strategies can help in the fight. Mowing can destroy the stalks and prevent seeds from spreading, but if done too late, it may worsen the problem by spreading seeds. Hand pulling can be effective for smaller infestations, as the plant is a biennial and will not regrow once removed. Always bag pulled plants immediately and discard them in the trash as a general safety precaution. While touching the plant itself won’t cause immediate harm, wearing gloves and long sleeves helps to protect your skin from rashes caused by contact with the plant.
Dig Deeper
For more information on invasive species and native plants, please see the resources listed below.
Weed Identification
Native Species
- Alberta Native Plant Council – Website
- ALCLA Native Plant Nursery – Website
Grow Me Instead – Plant Wise Brochure
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Agriculture