Wisteria sinensis

Wisteria sinensis clings to supporting plants or man-made structures by counterclockwise-twining stems. The leaves are shiny, green, pinnately compound, 10–30 cm in length, with 9-13 oblong leaflets that are each 2–6 cm long. The flowers are white, violet, or blue, produced on 15–20 cm racemes before the leaves emerge in spring. The flowers on each raceme open simultaneously before the foliage has expanded, and have a distinctive fragrance similar to that of grapes. Though it has shorter racemes than Wisteria floribunda (Japanese wisteria), it often has a higher quantity of racemes. The fruit is a flattened, brown, velvety, bean-like pod 5–10 cm long with thick disk-like seeds around 1 cm in diameter spaced evenly inside; they mature in summer and crack and twist open to release the seeds; the empty pods often persist until winter. However seed production is often low, and most regenerative growth occurs through layering and suckering. All parts of the plant contain a glycoside called wisterin which is toxic if ingested and may cause nausea, vomiting, stomach pains, and diarrhea. Wisterias have caused poisoning in children of many countries, producing mild to severe gastroenteritis.