Images of Alaskan Fireweed. How’d it get that name? The name fireweed stems from its ability to colonize areas burned by fire rapidly. It was one of the first plants to appear after the eruption of Mt. St. Helens in 1980. Known as rosebay willowherb in Great Britain, fireweed quickly colonized burned ground after the bombing of London in World War II, bringing color to an otherwise grim landscape.