Black Henbane
(Hyscomus niger)

By Jon Peterson

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

Introduction
     Black henbane, or Hyoscyamus niger, is a plant that has served many purposes and still does, even though it is a noxious weed. It can be used for medicinal purposes, as a hallucinogen, for poison by witches in the middle ages, and for ornamental purposes. It is also a poisonous plant. Any part of the plant can be toxic to humans.

Identification
     Black henbane consists of both annuals and biennials, which differ in form. Annuals are a much smaller weed than the biennials, which can grow to 4 feet in height. Annuals are also a lot less common than the biennials. The entire plant is covered with greasy hairs. Leaves are up to 8 inches long and 6 inches wide. Black henbane flowers from May until September. The flowers are 5 lobed, up to 2 inches across, and greenish-yellow in color with deep purple veins and throats. The calyx forms a 1-inch, egg-shaped  fruit.

Background
     Black Henbane is a native of Europe and has been cultivated as an ornamental. It has spread throughout the United States and is a common weed of pastures, fence rows, roadsides, and waste areas. Black Henbane contains hyoscyamine and other alkaloids which can cause livestock poisoning. It is considered a poisonous plant to humans.

Habitat and Distribution
    Black henbane is a plant that will grow in a large variety of soil. It does however grow best in rich soils. It also prefers sandy areas near the ocean. It apparently does nothing to contaminate the soil for native plants. 
     This plant is found all over Europe and the Mediterranean, where it is native. In North America it is found mostly in the northern United States and southern Canada. It was introduced as mainly an ornamental plant to the US. 

http://plants.usda.gov/cgi_bin/topics.cgi?earl=noxious.cgi

Biology and Ecology
      The plant reproduces through seeds. The egg-shaped fruit opens when it reaches maturity thus releasing its seeds. It can produce anywhere from 10,000 to 500,000 seeds per plant. Seeds can remain in the soil 1 to 5 years before germination, after that they are infertile.

Ecological and Environmental Impacts
     The effect of black henbane on the water supply is also noteworthy. It is very competitive for soil moisture and will out compete native plants for the precious resource.
     Henbane affects plant communities in a couple of different ways. One way is that it produces a persistent litter that effects the germination and growth of native species. It also creates shade that will help black henbane out compete native species for light.
     Animal communities are also effected by black henbane. It is a highly toxic plant. It can kill cattle if it is ingested as well as humans. It is not however very palatable because of its smell and taste. Livestock will only eat henbane if it is the only thing left to eat.

Economic and Human Impacts Options
     There are couple of different costs associated with the ecological impacts of black henbane. One of the costs would be the loss of desirable forage. Black henbane is more competitive for resources than native plants and will take over if not controlled in time. Another cost would be the loss of livestock. Black henbane is poisonous to livestock and will cause them death or sickness. It is also highly toxic to humans. It can cause skin irritation if it is touched with bare skin. It will also cause death to humans if it is ingested. 
      Black henbane can affect the cost of production in several ways. One cost is what you use to get rid of the weed. Control methods can be expensive and time consuming. Another cost would be if it contaminated a crop that was going to be used for livestock consumption. If there was enough of the plant in the crop it could still cause death or sickness to livestock. This is another cost is the loss of desirable forage for livestock. Livestock will lose or not gain weight because there is less forage available to them.

Management Options
     There are many different management options for the control or eradication of black henbane. The best option for control is to prevent infestations of henbane in the first place. After prevention the best two options are cultural control and herbicide control. 
     Prevention is the best for control of henbane because it is the cheapest. It also has the least amount of ecological damage. This can used to either totally prevent black henbane infestations or preventing current populations from spreading. To do this you need to monitor the land and populations of weeds. Stay informed on new technologies and control methods used for control of black henbane. Help to educate other people about the problem. 
     There are different methods in the use of cultural control. One method is to simply cut down the plant. This is an option if there is a small population to control. If this option is used then the plants need to be bagged and taken away from the removal site. If there is a seed pod there needs to be great care to make sure they are not harmed and no seeds are dispersed while getting rid of the plant. Another option to use is burning the plant. This method can be effective if it is used before the flowering stage and the seeds are dispersed. 
     Herbicide use is the most commonly used and is very effective in the control of black henbane. Some of the chemicals used include Picloram, Dicamba, Metasulferon, and 2-4D. Herbicides are most effective on black henbane if they are sprayed between the rosette and the bolt stage of the plant. For more information on herbicide use click here http://weeds.ippc.orst.edu/pnw/weeds
     Some management options that are not used for black henbane are grazing and biological control. Grazing is not an option because black henbane is poisonus to livestock. Biological is not an option because there is not an approved biological agent to use.

Additional Resources
"Black Henbane". [online]. Retrieved February 12, 2003 from: 
     http://www.twinfallscounty.org/weeds/black%20henbane.htm

Calihan, Robert H. and Miller, Timothy W. "Black Henbane" [online] retrieved 
     February 12, 2003 from:
     http://www.oneplan.org/crop/noxweeds/nxweed01.htm

Mitich, Larry W. (1998, December 11). "Black Henbane" [online] retrieved 
     February 12, 2003 from:
     http://www.wssa.net/subpages/weed/weedstoday/henbane.htm

"Southwest Exotic Plant Information Clearinghouse"[online] retrieved 
     February 12, 2003 from:
     http://www.usgssrv1.usgs.nau.edu/swepic/asp/aprs/question.asp?location=cs&svmbol=hyni