Polygonum patulum, called tree hogweed, is a species of flowering plant in the knotweed family. It is native to the Mediterranean region, eastern Europe, the Caucasus, Siberia, Central Asia, Mongolia, and the Province of Xinjiang in northwestern China.Flora Italiana, Polygonum patulum Bieb.Plantarium, Polygonum patulum M. Bieb., Описание таксона, Русскоязычные названия in Russian with many photos and partial distribution mapFlora of China, Polygonum patulum Marschall von Bieberstein, 1808. 展枝萹蓄 zhan zhi bian xu It has also become sparingly naturalized in scattered locations in Australia and North America.Atlas of Living Australia, Polygonum patulum M.Bieb., Tree HogweedBiota of North America Program 2014 county distribution map
Description Polygonum patulum is an erect or semi-erect annual herb up to tall. Leaves are green or blue-green, up to long. Flowers are green, pink, or white.Flora of North America, Polygonum patulum M. Bieberstein, 1808.
References
External links line drawing, Flora of China Illustrations vol. 5, fig. 239, 3-4 photo of herbarium specimen at Missouri Botanical Garden