This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Perennial. Propagates by seeds. Time of bloom: July to August. Seed-time: August to September. Range: Labrador to Alaska, southward to
North Carolina and Kansas, in the Rocky
Mountains to Arizona, and on the Pacific
Coast to California. Habitat: Low grounds and thickets; land that has been newly cleared or burnt over.
Stem two to six or more feet in height, somewhat woody, rather stout, erect, simple or branched from the base, usually reddish, smooth or sometimes finely hairy above. Leaves alternate, narrow lance-shaped, thin, entire or minutely toothed, pale beneath, with very short petioles and pinnate veins united in marginal loops. Flowers in large terminal racemes, purple, magenta, pink, or sometimes white, very showy; petals four, rounded and entire, with twice as many stamens and an elongated pink style with fourparted white stigma; ovary below the calyx-tube and four-celled. The plant is good bee pasture, generous of both pollen and nectar. Capsules two inches or more long, obscurely four-sided, reddish brown, velvety-hairy when young, many-seeded, opening at the summit. Seeds small and brown, tufted with white hair finer than thistle-down, by which they are widely wind-sown. (Fig. 205.)
Fig. 205. - Great Willow-herb (Epilobium angustifolium). X 1/4.
Close cutting or hand-pulling before the development of seeds; destruction of the perennial roots by cultivation of the ground.