Also called Reynoutria japonica and Polygonum cuspidatum.
Part of
buckwheat/knotweed family Polygonaceae.
Native to 🇨🇳 China, 🇯🇵 Japan and 🇰🇵 🇰🇷 Korea.
Invasive > learn+quiz
Invasive > 🌐︎ global
Invasive > 🌐︎ various
Invasive > USA+Canada
Invasive > report it!
Invasive > USA
Invasive > Michigan
prohibited in Michigan, incl. seeds, fragments and derivatives 
inv. trading card
🚼︎ For kids! This plant described in invasive species placemat
series.
Purposely introduced as an ornamental, in North America, 🇪🇺 Europe and 🇦🇺 Australia Japanese Knotweed forms extremely dense monocultures, spreads rapidly by roots, plant fragments, and rhizomes, destroying building foundations, cracking drain pipes, and eroding streambanks. It can grow through
concrete and asphalt.
It also releases
allelopathic chemicals
into the soil
, ☠︎ toxic
to native ecosystems.
Japanese Knotweed is restricted (illegal to possess or introduce) in areas of North America, 🇪🇺 Europe and 🇦🇺 Australia.
For full effect, view the three videos
↖ above or to left by selecting the video image, choosing Part 1 then 2 then 3,
then icons
YouTube (if present),
⏯︎ ☒ Skip Ads (if present),
㏄ captions
(if you wish),
⛶ fullscreen, and ▶︎ Play.
Japanese knotweed is adapted to grow in 🌋︎ volcanic soil — like ⛰ basalt! No wonder it grows through concrete and asphalt!
Uses by native peoples
(Ethnobotany database)
Recipes