Black nightshade—also called deadly nightshade–is the most common of several nightshade weeds. The nightshades are close relatives of tomatoes, potatoes, and eggplants. The leaves and berries of nightshades contain toxic alkaloids that are harmful to humans and animals.
Hairy nightshade and cutleaf nightshade are two other garden weeds similar to black nightshade. Nightshades are annuals and sometimes short-lived perennials.
Description and Life Cycle of Black Nightshade:
- Grows from 6 inches to 2½ feet tall with branching stems that may stand erect or lie on the ground.
- Stems are triangular shaped.
- Leaves are egg shaped, with smooth or wavy margins.
- Leaves are alternate on the stem.
- White or pale blue flowers are five petaled and resemble tomato flowers, drooping in clusters.
- Small berries in bunches are dull green when young and black when mature; berries are toxic but not very palatable.
- When plant parts are eaten they can cause vomiting, abdominal pain, bloody diarrhea, difficulty breathing, lack of coordination, weakness, collapse, convulsions and possible death. Animals, pets, and humans should not eat black nightshade.
- Reproduces by seed; seeds are small, yellow-to-brown, dull, and flattened.
- Blooms in late summer.
- Commonly found in disturbed soil or sometimes where root crops have grown.
- Member of the Solanaceae family; same as tomatoes, potatoes, and eggplants.
Root System: Nightshades have a slender taproot that branches frequently.
- Remove young plants immediately; dig out the taproot.
- Do not let the plant flower or drop seed.
- Mulch to prevent seeds from germinating.
- Place clear plastic on infested areas and solarize to kill seed.
- Nightshades can host Colorado potato beetles and late blight fungus.
Range: Eastern half of the United States and southeastern Canada.
Scientific name: Solanum nigrum (black nightshade); S. sarrachoides, hairy nightshade; S. triflorum, cutleaf nightshade.