Knotweed, also called Himalaya fleece flower, is a small and attractive bloom, unlike its close relative Japanese bamboo, Persicaria cuspidatum, which is one of the most pernicious weeds in America -- a plant that is as happy along a roadside as it is in a garden. The former genus name for knotweed, Polygonum, is from the Greek for "many knees," referring to the large number of joints found on the stems.
Description of knotweed: Himalaya fleece flower is a tufted ground cover plant with dark green, tapered leaves on creeping stems. Tiny, bright rose flowers bloom in dense spikes about 8 inches high from late summer into fall. Ease of care: Easy.
Growing knotweed: This plant requires good soil, preferably slightly moist, in full sun.
Propagating knotweed: By division in spring.
Uses for knotweed: The plant is good as a ground cover or as an edging plant for the bed or border. It is especially valuable because the plant sends up new flowers over a long period.
Knotweed related species: Persicaria bistorta Superbum is a very attractive plant for the border that bears 6-inch pinkish spikes of flowers on 2-foot stems. Plants prefer light shade in areas with hot summers. Soil should be moist. Persicaria amplexicaule, mountain fleece flower, is a long-blooming, leafy plant with thin spires of red flowers. Firetail is a popular selection with cerise flowers. Rosea has fatter, pink inflorescences.
Knotweed related varieties: Darjeeling Red has pale pink flowers when new, turning to a deep rose-red as they mature; Donald Lowndes has flowers of a light pink.
Scientific name for knotweed: Persicaria affineWant more gardening information? Try: