Also called Sakhalin knotweed, オオイタドリ (ooitadori), Горец сахалинский, Гречиха сахалинская, Fallopia sachalinensis and Polygonum sachalinense.

"Giant knotweed" may also refer to hybrids of this plant with its very-close sister-species Japanese knotweed  Fallopia japonica, with the hybrids known as bohemian knotweed  Reynoutria × bohemica,  Fallopia × bohemica, and Polygonum × bohemicum.

Part of buckwheat/knotweed  family Polygonaceae.

Native to far eastern 🇷🇺 Russia, and northern 🇯🇵 Japan.   Invasive > learn+quiz Invasive > 🌐︎ various Invasive > 🇨🇦 🇺🇸 Canada+USA Invasive > report it! Invasive > 🇺🇸 USA Invasive > Michigan   Treatment methods and timing (40–45°N lat.).  Adobe Acrobat Reader file   I have also heard of controlling this plant using ⚶🐐︎ prescribed browsing / goatscaping.

Uses by native peoples
(Ethnobotany database)

Learn more about giant knotweed Reynoutria sachalinensis

🔍︎ 🔍︎ images Discover Life Encyclopedia of Life Michigan Flora Flora of North America Kew Plants of the World PLANTS db (USDA) USFS Wikipedia

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🏠︎ terrestrial 🌾︎ herbaceous plants

Japanese knotweed  Fallopia japonica