Himalayan knotweed is a beautiful plant, which is however a persistent weed. Introduced for garden purposes in the West in the 19th century from the Himalayas, it is now established in a few places in the wild - on roadsides, slopes etc. The leafy shoots grow up to about 6 feet high from underground rhizomes and produce clumps of small white or pale pink flowers in late summer. The stems take on a striking red color, and the small white flowers, occuring in rich branched clusters, also have a reddish tinge. The inflorescences are panicles occuring at the end of branches. Flowers have white or pinkish petals whic are oblong to obovate in shape. Stamens are prominent with red or purple anthers. Flowering August-October.