persicaria amphibia blooms in july in a pond. potsdam, germany

germany persicaria amphibia blooms july pond amphibium longroot smartweed water knotweed amphibious species plant family potsdam flowering plants polygonum nature beautiful summer green garden background flora natural outdoor leaf lotus flower lake park floral environment leaves color blossom waterlily colorful aquatic wildflower blooming petal pink bloom season germany pond bistort family