Fireweed definition

Any of various plants of the genus Epilobium, especially E. angustifolium (syn. Chamerion angustifolium ), having long, terminal, spikelike clusters of pinkish-purple flowers.

Any of several weedy North American plants of the genus Erechtites in the composite family, having small white or greenish flowers grouped in discoid heads.

Any of a number of plants that grow readily on cleared or burned-over land; esp., a species (Epilobium angustifolium) of willow herb, with purplish-red flowers.