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Weed & Pest

Black henbane added to Wyoming’s state list of designated noxious weeds

Written by Natasha Wheeler

With a unanimous vote on Feb. 11, the Board of Agriculture passed a resolution to add black henbane to the state’s list of designated noxious weeds.

“At the public hearing, there were folks who commented in support of the resolution, but there were no comments opposed to it,” comments Slade Franklin, weed and pest coordinator with the Wyoming Department of Agriculture.

The board took action on the resolution in a business meeting immediately following the public hearing.

“It was a straightforward hearing, and there wasn’t anything too concerning,” he notes.

Black henbane has already been listed in numerous Wyoming counties as a noxious weed.

“Concern had grown to almost all 23 counties in the state. It was getting to the point where we needed to start addressing it from a state level,” Franklin says.

The weed is especially prevalent along pipelines and in riparian areas.

“Black henbane likes disturbed lands,” he explains. “Especially in the southern part of the state where vegetation is scarce, more weeds in general are likely to come in after a disturbance such as when a new pipeline is put in.”

In Teton County, the weed is often a problem around new home construction.

“It is diverse in terms of areas that it can attack,” Franklin notes.

When the plant reaches maturity, a thickened lid pops off of the urn-shaped fruit, spilling black seeds. A single plant can produce up to half a million seeds.

“I’ve had reports on black henbane from areas all over the state,” states Franklin.

Last year, the Board of Agriculture wrote a letter to the Weed and Pest Council, asking them to consider adding black henbane to the state’s designated weed list.

“The rules and regulations state that a resolution must start with a weed and pest district request to the council, who then moves it forward to the Board of Ag for consideration,” he says.

After the board’s request, three different weed and pest districts moved forward with a resolution.

“We moved one of the resolutions forward,” Franklin states. “It is the 26th weed on our designated list.”

Black henbane is an annual or biennial plant that grows up to three feet tall, and the entire plant is covered with greasy hairs. Leaves are up to eight inches long and six inches wide, shallowly lobed and heavily scented.

“It is a poisonous plant, so there are also concerns from an agricultural perspective about its toxicity,” adds Franklin.

Generally, livestock will avoid the weed unless it is the only available forage.

“There is potential for concern in targeted grazing or with livestock that is not used to it,” he adds.

In controlled dosages, alkaloids from black henbane are used in medications but the plant is also poisonous to humans.

“Black henbane is treatable,” Franklin continues, noting that there are several herbicide options for control of the plant.

Escort and Tordon are examples of herbicides that work effectively for controlling the weed.

“It’s not a matter of ‘can we treat this,’ it is a matter of ‘do we need to treat this,’ and that is why it has made it on the list,” Franklin explains.

Other common names for black henbane include insane root, stinking nightshade, fetid nightshade and hog’s beam.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at This email address is being protected from spambots. You need JavaScript enabled to view it..