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


Jake said...

Hmmm... I have seen this weed before never knew what it was but I will be checking for it in the future.

Middle Earth Garden said...

Jake: Do you recall where have you seen the weed? I'm curious how widely it is spreading.

Middle Earth Garden said...

Below is some good advice I came across regarding noxious weeds and wildflower mixes on the Rocky View County website:



Although many of us like the idea of a wildflower pasture there are some precautions we must take before selecting seed. Several wild flower mixes contain plants that are defined as noxious weeds in Alberta. The same goes for grass seed and hydro-seeding mixtures.

Once a noxious weed is established, it is the owner’s responsibility to control weeds on their property. A list of noxious and prohibited noxious weeds can be found on

You have the right to request a certificate of analysis which will identify the purity of seed you are purchasing. Do not assume that your contractor or retail outlets are taking these precautions for you. If you are interested in a native garden or wild flower pasture purchase from a reputable company that specializes in plants and seed native to Alberta.

Check out these websites:

ALCLA Native Plant Restoration Inc.

Bow Point Nursery

Bedrock Seed Bank

Wild About Flowers

Black Henbane is unlikely to be a concern in such wildflower seed mixes, but other smaller noxious weeds could be a conceren worth investigating.

crazypiazza said...

you wrote it is annual or perennial i thought henbane niger was only annual,is their sub kind or variety that is perennial ?thanks

Middle Earth Garden said...

crazypiazza: It probably depends on the conditions whether it will come back the next year as a perennial or not (i.e. zone and particular weather in a given year).

Are you planning to grow it as an ornamental plant? Please don't if on the Canadian prairies! It is not likely as invasive in certain other climates, but you should check your local invasive species list first before planting. Plus it is poisonous. I'm sure there are better choices.

crazypiazza said...

i just threw few seeds in a pot here where i live in Tuscany,considering climate here,you think it will take over the entire garden?

point two: the single plant is not perennial ..!? but it might reseed making others plants by itself so you said that they would be classified as perennials?

Middle Earth Garden said...

crazypiazza: I really have no idea if the plant will be perennial for you or not. I have no experience growing the plant, and do not intend to.

There are legal implications if you plan to grow a noxious weed in Alberta. I would suggest you review the Alberta Weed Control Act and Regulation:$department/deptdocs.nsf/all/acts6156

I am not famaliar with the details of the law, but the point is to minimize the chance of spreading the weed.

By willfully growing the weed, you leave the opportunity open for it to spread unecessarily. This potentially creates a nuisance to your neighbours and costs to the City for weed control.

You cannot completely control where the seed will end up unless you grow it in a sealed container (which is not practical).

I strongly suggest destroying the seed and finding a native or non-invasive plant to grow instead, there are many options to choose from. Check out your local greenhouse.

The Blog Fodder said...

The whole plant is poisonous? Cool. Probably would make excellent herbal tea for family members who over stay their welcome?
I remember we had a patch of Toad Flax once, long ago. The RM sterilized the soil so nothing would grow on it for years.

Ceska said...

I don’t know what to say. This is definitely one of the better blogs I’ve read. You’re so insightful, have so much real stuff to bring to the table. I hope that more people read this and get what I got from it: chills. Great job I can’t wait to read more, keep them coming! .

Middle Earth Garden said...

Ceska: Thanks for the positive feedback. Makes the time spent on the blog worthwhile (some days I wonder).

However, I should warn that actual gardening work always takes precedence over garden blogging ;-) On "rainy days" I'll post some updates when I can.

Middle Earth Garden said...

For my own record, I spent about 3 hours over two sessions in the past week and managed to remove likely 95% of the Black Henbane in the Nose Creek Park from Deerfoot to Harvest Hills Blvd (or at least all of it over one foot tall). I think the City has been removing some as well.

The ground was wet from recent rain and 90% of them pulled out with little effort, roots and all. A few were stubborn. Yellow dishwashing gloves work perfect for the task, besides being poisonous the plants are somewhat slimy.

Middle Earth Garden said...

Update on weed pulling: Spent another hour or so pulling some Black Henbane stragglers over same area as previous comment.

Maybe 10 to 20% the quantity as pulled before, but took longer per plant as they were hiding among other plants including tall plants with burr-seeds (OK add 15 minutes for removing burrs from clothes).

I am likely breeding the plants to grow shorter and go to seed faster. Will check again in another month.

Dan Johnson said...

I am very interested in insects found on henbane/nightshade plants. I can supply a net and sticky cards to place near them. I would also pay for shipping of leaves, if they seem to have small insects adhering to the underside of the leaves. In fact, I would alsosupply a sticky card to gardeners with tomatoes and potatoes, just to check. dan.johnson @

Samantha Nickerson said...

I just found a few of these plants in my field near Cochrane. I didn't know what they were so I posted a photo on my FB. I'll be destroying them all today!