Reynoutria japonica, synonyms Fallopia japonica and Polygonum cuspidatum, is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. Common names include Japanese knotweed and Asian knotweed. It is native to East Asia in Japan, China and Korea. In North America and Europe, the species has successfully established itself in numerous habitats, …

虎杖（学名：Reynoutria japonica），別名假川七、土川七、紅三七、三七 、日本虎杖或日本蓼，是一種蓼科何首乌属植物。被國際自然保護聯盟物種存續委員會的入侵物種專家小組（ISSG）列入世界百大外來入侵種 。