Knotweed

With a decent flowering period from late spring to midsummer, the vigorous Knotweed is an excellent choice for the damp garden. The bottlebrush-like, tiny mauve-pink flowers are packed tightly together on thin stems, above the dock-like foliage. The best planting position is at the edge of a pond or in a bog garden, where it quickly spreads forming impressive colonies up to 1m wide. 'Superba' is better than the species because it has larger flowers. It has been given the Award of Garden Merit (AGM) by the Royal Horticultural Society.