Fireweed (Epilobium angustifolium) is a member of the Onagraceae or Evening Primrose family. It is a single stemmed perennial which grows between 3- and 10-feet tall with numerous, crowded, alternate, lance-shaped, sessile leaves, each of which is about 6-inches long and 1.2-inches wide. The many magenta (sometimes white) tubular flowers are from 0.75- to 1.6-inches wide. They occur along an elongated flower cluster with single flower stalks attached along the side of a common axis. Each flower head has four egg-shaped petals and a stigma that is usually shaped like a cross. The flower buds usually droop, but the reddish seed pods are ascending. It flowers from mid-summer to the first frost.
Fireweed is found in higher elevations, usually in disturbed areas such as recently logged forests or those that have suffered a fire. It is from the colonization of burned areas that the plant got its name. It is found throughout throughout the temperate regions of the Northern Hemisphere. In some parts of Canada it is known as great willowherb.
In Britain and Ireland as rosebay willowherb. In the United Kingdom it is also known as bombweed as a result of its rapid appearance on city bomb sites during the Blitz of World War II.