Bittersweet nightshade arrived from Eurasia and has naturalized thoroughly across North America, most successfully in moist and disturbed places: wetland margins, thicket edges, pond banks, and the tangled shrubbery of neglected gardens. A scrambling semi-woody vine reaching 2 to 10 feet in zones 4 to 8, it climbs without tendrils by weaving through surrounding vegetation, its purple-tinged young stems hardening to greenish-brown at the base. The summer flowers are a genuinely striking thing: five purple petals swept back to reveal a projecting column of yellow stamens, the whole flower looking more like a cyclamen than anything one would expect from this genus.

The berries that follow are the vine's most arresting quality, hanging in clusters that display every stage at once: green, pale orange, and finally a rich shining red, all ripening at different rates on the same stalk through summer and into fall. The effect is decorative, and it has drawn gardeners in despite the plant's invasive status in several northeastern and Pacific states. All parts are toxic to humans, pets, and livestock; contact with crushed leaves can irritate skin. Where control is needed, small infestations yield to manual removal of the root crown, but established plants in moist soil require persistent effort or targeted herbicide.