Fallopia sachalinensis
（重定向自Giant Knotweed）
Fallopia sachalinensis (giant knotweed or Sakhalin knotweed Japanese オオイタドリ ooitadori, Russian Горец сахалинский, Гречиха сахалинская; syn. Polygonum sachalinense F.Schmidt, Reynoutria sachalinensis (F.Schmidt) Nakai) is a species of Fallopia native to northeastern Asia in northern Japan (Hokkaidō, Honshū) and the far east of Russia (Sakhalin and the southern Kurile Islands).