Saturday, January 15, 2011

Black Henbane (Hyoscyamus niger) - Alberta Invasive Species Series

Catching up on some contemplated summer posts that never materialized, the following describes my encounter last summer with the intimidating (cue scary music): BLACK HENBANE (Hyoscyamus niger), also known as Stinking Nightshade . Both names sounding quite ominous. And for good reason.

I encountered a patch of these evildoers in West Nose Creek Park. Not knowing what they were at the time, I took some photos and did some research. The plants were hard to miss, standing up to four feet tall!

As someone who grew up on the prairies and never having seen this plant before, I figured such a large and obtrusive plant must be an invasive species. This narrowed my search considerably. Once identifying the plant, I washed my hands after learning of its toxic nature.

Black Henbane is classified as "Noxious" by the Alberta Invasive Plants Council [1]. Some interesting characteristics of the plant are summarized below (from [1]):
  • Annual or Perennial
  • Reproduces by seed only (see photos below of seed pods)
  • Native to Eurasia
  • All parts of the plant are poisonous to animals (including humans)
  • A single plant can produce up to 500,000 seeds per season
  • Seeds are typically viable for up to four years
  • Prefers sunny areas
Proliferate Seed Pods (above)

West Nose Creek Park (natural area), above

I notified the City of Calgary about the weeds presence and offered my volunteer labour to help remove them. Being such a large bushy plant, I envisioned that hand removal would be quite easy with a pair of rubber gloves and garbage bags. But then what to do with the remains to prevent further spread?

I received no response from the City, but a few weeks later the plants had been removed and the City had done some spot spraying for invasive weeds, primarily Yellow Clematis (Clematis tangutica) which has really taken hold in the park. I'll be keeping my eye out for their potential return.

[1] Black Henbane - Alberta Invasive Plants Council