one spikelike inflorescence of red knotweed flowers

amplexicaulis bistort bloom blossom bright close closeup cluster color colorful decorative dutch erect fleece flora flower flowerbed flowers foliage foreground garden green group head herbaceous inflorescence knotweed knotweeds leaf leaves natural nature netherlands outdoor perennial persicaria plant polygonaceae purple red reddish rural smartweed smartweeds spike spikelike stem summer texture vivid