green and dried stems of a perennial garden and weed plant sakhalin buckwheat, polygonum sachalinense, reynoutria

beautiful plant nature leaf green background season garden sakhalin spring species seasonal autumn biology bloom blossom branch britain edible exotic fallopia floral flower foliage giant grow growth gynodioecious sprout japonica japanese herbaceous stem wild heartshaped shoot knotweed landscape sachalinensis invasive summer perennial weed stalk pest leaves