Bittersweet nightshade (Solanum dulcamara) is a perennial introduced to much of temperate North America from Eurasia and Northern Africa. This invasive weed is found in moist waste places, thickets, roadsides, open forests and clearings. A member of the Nightshade Family (Solanaceae), bittersweet nightshade is also commonly called climbing nightshade and European bittersweet, among other names.
Spread by rhizomes, bittersweet nightshade stems are vine-like and tend to climb or sprawl over other vegetation. Older stems can be somewhat woody. These purple and slightly hairy above-ground branches die back each year.
Some of the alternate, stalked leaves are unlobed and egg shaped to somewhat heart shaped. Other leaves have a pair of ear-like lobes or leaflets at their base.
The inflorescences arise from the leaf axils or the ends of the stems. The blue-violet bittersweet nightshade flowers resemble shooting star or tomato flowers. The five pointed tepals (not distinctly a petal or sepal) are fused into a short tube at the base with reflexed lobes. The five stamens join together into a conspicuous yellow cone.
Bittersweet nightshade fruits are berries arranged in open clusters. The berries are originally green and mature into a bright red color. The yellow seeds are circular and flat sided. The fruits resemble small tomatoes. Birds are primarily responsible for dispersing bittersweet nightshade seeds.
All parts of bittersweet nightshade are poisonous to humans and livestock, although the stems are less toxic. Eating bittersweet nightshade can cause nausea, diarrhea, vomiting and dilated pupils. Overdosing results in paralysis of the central nervous system, convulsions and, if enough of the plant is ingested, death.
That said, bittersweet nightshade was thought to be effective against witchcraft and the”evil eye” if hung around the neck. Historically herbalists used juice from the plant to dissolve blood clots resulting from injury. It has been shown that alkaloids, found in the unripe fruits, the flowers and the roots of bittersweet nightshade, inhibit the growth of certain bacteria. In Germany, preparations from the stem are approved for external use against chronic eczema. As with all toxic plants, I prefer not to test my luck.
Solanum means “quieting” in Latin and refers to the narcotic properties of some species in this genus. The species designation means “bittersweet” in Latin (“dulcis”/sweet and “amarum”/bitter). Apparently the rind of the stem, according to a writer in the 1500s, “first tasted is bitter, afterwards sweet”.
These bittersweet nightshade plants were photographed along the Rail Trail at Ankeny National Wildlife Area south of Salem OR (Marion County) in late July.