Black henbane [Hyoscyamus niger L.][HSYNI][CDFA list: C] Photographs

[Back to Index]


SYNONYMS:common henbane, fetid nightshade, insane root, hog’s-bean, jupiter’s-bean, henbell, hyoscyamus, symphonica, cassilata

GENERAL DESCRIPTION:Coarse, erect biennial or summer annual to 1 m tall. Foliage is covered with sticky glandular hairs and has a foul odor. Black henbane has been used medicinally for centuries and is commercially cultivated in Europe for its alkaloid compounds. All plant parts contain tropane alkaloids (hyoscyamine, hyoscine or scopolamine, atropine) and are toxic to humans and animals when ingested. Livestock rarely consume plants because of the unpleasant odor and bitter taste. Introduced into Eastern North America from Eurasia as a medicinal herb.

SEEDLINGS:Cotyledons lanceolate to oblong, 3-5 mm long, 1-2 mm wide, with a few hairs on the basal margins. Lower midvein terminates with a gland. Stalk below the cotyledons (hypocotyl) short, visible above ground only at the earliest stage. Subsequent rosette leaves alternate, +/- oblong, often with petioles nearly as long as the blades. Margins entire to slightly wavy. Veins conspicuous, depressed on the upper surface, prominent below. Petioles and veins covered with long glandular hairs.

MATURE PLANT:Stems erect, leafy, branched (biennial form) or few-branched (annual form), densely covered with long glandular hairs. Leaves alternate, gray-green, covered with short glandular hairs, short-stalked (lower) to sessile (upper), oblong to lanceolate, 5-20 cm long, coarsely toothed to acutely pinnate-lobed, with conspicuous pale veins covered with long glandular hairs. Lower leaves short-stalked, upper sessile.

back to top of page

ROOTS and UNDERGROUND STRUCTURES:Taproot thick, fleshy.

FLOWERS:June-September. Racemes terminal, leafy, one-sided, +/- coiled at the tips, with flowers solitary in leaf axils below. Petals fused, funnel-shaped, unequally 5-lobed, oblique at the opening (limb), 2-3(4) cm long, pale (greenish-) yellow with conspicuous purple veins and a purple throat. Sepals fused, urn-shaped, 5-lobed, densely covered with long glandular hairs at the base, 1-1.5 cm long, enlarging to 2.5-3 cm long in fruit. Lobes acute, spreading, stiff. Stamens 5 (2 short). Filaments hairy. Anthers purple. Annual plants often have paler flowers and bloom later than biennials.

FRUITS and SEEDS:Capsules ovoid, 0.8-1.5 cm long, 2-chambered, open by a thick lid at the top (circumcissle), loosely enclosed and concealed by a stiff, prominently veined calyx (sepals collectively). Seeds numerous, brown to gray, deeply pitted, flattened, ~ 1.5 mm long, variably shaped, oval to +/- square, contain a higher concentration of alkaloids than leaves or roots.

HABITAT:Disturbed open sites, roadsides, fields, waste places, abandoned gardens. Grows best in sandy or well-drained loam soils with moderate fertility. Does not tolerate waterlogged soils.

DISTRIBUTION: At publication time, no infestations are known to exist in California. Plants previously eradicated occurred in Modoc, Siskiyou, and Mendocino cos. Scattered throughout most of the U.S. and Canada.

PROPAGATION/PHENOLOGYReproduces by seed. Seeds that mature early in a season typically produce biennial plants. Seeds maturing late in a season often produce annual plants. Newly matured seeds germinate without light. Seeds that become dormant germinate best when exposed to light. Under field conditions, seed can remain viable for ~ 4 years. Biennial seedlings require a cold moist period to induce stem elongation and flowering. In colder, more northern regions the proportion of annual plants is higher than in more southern clines.

MANAGEMENT FAVORING/DISCOURAGING SURVIVAL:Prevent seed production by cultivation, hand pulling, or mowing plants. Plants with mature fruits can be burned to kill seed.

SIMILAR SPECIES: Black henbane is unlikely to be confused with other species in the nightshade family because of its distinctive flowers and fruits.

back to top of page


Prevention and control: Black henbane and prickly comfrey are native to Europe, and were likely introduced to the United States as medicinal herbs. Both species may be very toxic to humans and animals, although grazing animals will not consume black henbane, unless other forage is unavailable. Black henbane is in the Solanaceae family and prickly comfrey is in the Boraginaceae family.
Black henbane was found in Modoc, Siskiyou, and Mendocino Counties, but has been eradicated. No new populations have been detected in California. However, it is occasionally found throughout the United States and has repeatedly demonstrated its ability to escape cultivation. It may live as an annual or biennial and reproduces solely by seed. The entire plant has an extremely foul odor. Any plants found should be reported to the County Agricultural Commissioner and immediately destroyed. Plants should be hand pulled (gloves are strongly recommended) or dug, making sure that the thick, fleshy, taproot is completely removed. Plants detected with mature fruits should be carefully placed in bags to prevent seed dispersal, and the area should be monitored for new seedling emergence for at least four years. If the infestation is too large for hand pulling, a systemic herbicide, such as glyphosate should be applied. Glyphosate is nonselective, but should provide effective control. The area should be monitored after application and any escapes or regrowth should be retreated.
Prickly comfrey is well established in areas of the North Coast Range, and in the Sacramento Valley in Yolo County. The source of introduction into California is uncertain. It has been grown as a forage crop in Russia and as a herbal remedy around the world. It thrives on moist, fertile, soils and is cold tolerant to some extent. The perennial nature of this plant increases the difficulty in control. It tends to form large distinct clumps with a deep taproot and can produce new plants from small pieces of severed roots. There is no information regarding herbicide efficacy on prickly comfrey. However, glyphosate is effective for controlling rough comfrey. Retreatment may be necessary on large clumps if regrowth occurs. Repeated cultivation may be effective, but may also spread severed roots to new areas.

Diomaiuto, Bonnand J., Houivet, J. Y., and Picard, C. 1980. Vernalization and flowering in henbane (Hyoscyamus niger). Ontogenic research. Bulletin de la Societe Botanique de France 127:427-442.
Downs, R. J. and Thomas, J. F. 1982. Phytochrome regulation of flowering in the long-day plant, Hyoscyamus niger. Plant Physiology 70:898-900.
Harris, PJ C., Grove, C. G., and Havard, A. J. 1989. In vitro propagation of Symphytum species. Scientia Horticulturae 40:275-281.
lev, S. 2-1972. The biology of Hyoscyamus niger. Farmatsiya 22:39-45.
Mugnier, C. 1977. An attempt to replace vernalization by application of gibberellic acid in biennial Hyoscyamus niger L. Biologia Plantarum 19:40-47.
Whitson, T. D., Burrill, L. C., Dewey, S. A., Cudney, D. W., Nelson, B. E., Lee, R. D., and Parker, R. 1992. Weeds of the West. Jackson, WY: Western Society of Weed Science.
back to top of page