The Enemy - Black henbane (Hyoscyamus niger) is a Mediterranean native that was originally brought to this country as an ornamental and for medicinal purposes. It is a biennial plant that grows up to 4 feet tall. The leaves are greatly lobed with a very conspicuous mid-vein that runs the entire length of the leaf. The ivory with deep purple flowers form urn shaped seed pods along the stems that are filled with hundreds of seeds. Once the plant dies these seed urns break off and disperse the seeds everywhere. This plant is narcotic and poisonous to humans. Livestock tend to leave it alone, unless no other food source is available.
The Strategy - Black henbane invades fencerows, roadsides, ditch banks, and disturbed waste areas. It is even competitive enough to grow in established alfalfa fields. Its heavy basil rosette leaves cover the ground as to not allow other species to survive. As it undesirable to livestock it can go untreated until it becomes a large problem. When Palisades Reservoir went extremely low a number of years ago, this plant showed up. How it got there still remains a mystery as there is no large quantity of the weed up stream of the pond.
The Defense - Control of this species is fairly easy. As we discussed livestock will not eat it. If you see a few plants show up, simply dig them up, ensuring that you get at least 2 inches of the root below the ground. Make sure that you wear gloves as the plant will irritate your skin. DuPont’s Telar and Escort are the best herbicides to control this plant. Applications can be from early rosette to bud. As this plant is very hairy, a good quality surfactant should be used. Remember not to eat this plant and call your local weed authority for proper identification.
For more information, click on the link below to download the Idaho's Noxious Weeds Control Guidelines publication produced by the University of Idaho Extension.
U of I Idaho's Noxious Weeds Control Guidelines (183 KB PDF download)