Fireweed Gone to Seed – Fireweed is one of the many flowers appearing in Yellowstone National Park. It is usually the first flower to appear following a wildfire, hence its name. They are common in disturbed areas and along roadways. The flower blooms from bottom to top over the growing season. It is often said that you know when fall is about to arrive when the tops of the Fireweed are in bloom. When the plant has gone to seed you see this wonderful spiral tangle of cottony fibers that add yet another dimension to the fall colors that mark the area.