Ohio Perennial and Biennial Weed Guide

Family:

Nightshade Family (Solanaceae)

Other Names:

bitter nightshade, bittersweet, blue nightshade, climbing bittersweet, climbing nightshade, deadly nightshade, dogwood, dulcamara, European bittersweet, felonwood, felonwort, poison berry, scarlet berry, shooting star, violetbloom, woody nightshade.

Origin and Distribution:

After it was introduced into North America from Eurasia as a cultivated ornamental, bittersweet nightshade spread throughout the U.S. becoming most abundant in the eastern and north-central states. In Ohio, bittersweet nightshade is distributed throughout the state. The species can be found in thickets, hedgerows, ditches, stream banks, marshes, swamp forests, deciduous woods, waste areas, roadsides, railroads, orchards, and along the edges of agronomic fields. Bittersweet nightshade prefers rich soils in areas that tend to be moist or even waterlogged for a portion of the year. The weed tolerates shade.

Plant Description:

Bittersweet nightshade is a perennial climbing or trailing vine that reproduces by seeds and rooting at the nodes of the prostrate stems. It can be distinguished from other viney plants by its hollow stems that are woody at the base and oval leaves with pointed tips. Attached to the leaf stalk (petiole) at the base of larger leaves are 2 opposite lobes, which are absent in smaller leaves. Therefore, the plant has 2 leaf forms that, along with its blue-violet flowers and bright red berries, can be useful to distinguish bittersweet nightshade from other nightshade species. All parts of the plant give off a disagreeable odor when bruised.

• Seedlings and Shoots:

  Young stems and leaves are generally hairy

• Stems:

  Stems are hollow, slender, slightly hairy, and woody at the base. They may be green, dark red, or black and can grow up to 10 feet long. Stems either climb or trail along the ground. Prostrate stems are capable of rooting at the nodes.

• Leaves:

  Leaves are oval with a pointed tip. Larger leaves have 2 lobes or leaflets at the base while smaller leaves lack such lobes. Leaves are alternate (1 leaf per node), 2 to 5 inches long, dark green with a purple tinge, and attached to stems by way of long leaf stalks (petioles). Leaf edges are smooth. Foliage emits a strong unpleasant odor when bruised.

• Flowers:

  Flowers consist of 5 blue-violet (rarely white) petals that are united at the base, deeply 5-lobed and shaped like a star at the top, and about 1/2 inch wide. Emerging from the center of each flower is a yellow column composed of fused anthers. Flowers appear in branched, drooping clusters that attach to the main stem opposite the leaves.

• Fruits and Seeds:

  Fruits are oval, thin-skinned, juicy, bright red berries that are about 3/8 inch wide and contain many disk-shaped, light yellow seeds.

Similar Species:

Annual nightshade species (Solanum spp.) look similar vegetatively but they have white flowers and blackish berries while bittersweet nightshade flowers are blue-purple and its berries are bright red.

Biology:

Flowering occurs in May to September. In areas where winters are severe, plants usually die back close to the ground; but, in areas with milder winters, stems can persist becoming thick and woody. Bittersweet nightshade does not survive cultivation. Because it serves as an alternate host for such generalized pests as the Colorado potato beetle, bittersweet nightshade can cause indirect damage to crops.

Toxicity:

Leaves are considered moderately poisonous if ingested, and there is much disagreement over the toxicity of the berries. Some say that paralysis can result in humans that have eaten as few as 6 berries. Cases of poisoning in cattle, horses, and sheep have been documented. Concentrations of toxic compounds within plants may vary with growth stage, and chemical components may vary from one individual to the next. Regardless, leaves and berries of the plant should be regarded as toxic.

Facts and Folklore:

• 'Solanum' was derived from the same Latin root word as 'solace', and was likely given as a name for this weed because of its many medicinal uses.

• 'Dulcamara' is a combination of Latin words meaning "sweet-bitter".

• The common name refers to a toxin in bittersweet nightshade that is said to leave a bitter and then sweet taste if ingested.

• Bittersweet nightshade was used to treat asthma, bronchitis, jaundice, kidney problems, rheumatism, skin diseases, syphilis, and to counteract witchcraft.