knotweed japanese, village house path way stems invasive expansive species dangerous plants leaf, leaves asia reynoutria

knotweed reynoutria fallopia japonica invasive sakhalin expansive leaf species dangerous plants leaves fruits intruder sachalinensis neophyte way house path stem japanese village background blue sky asia japan reduces green wild wildflower biodiversity perennial projects eliminates gatecrasher soil contamination herbicides nature flower bushes calamity disaster large ecology environmental shadow european biomass