knotweed bloom invasive plant reynoutria flower or blossom bees fallopia japonica japanese, expansive intruder neophyte

achenes apis asia bee bees biodiversity biomass bloom blossom bushes calamity collect contamination dangerous disaster eliminates europe european expansive fallopia flower flowers flying fruits gatecrasher green herbicides honey insects intruder invasive japan japanese japonica knotweed large leaf leaves mechanically mellifera neophyte plants reduces reynoutria rhizome sachalinensis saw species wild wildflower