Eutrochium maculatum

Eutrochium maculatum, the spotted Joe Pye weed, is a North American species of flowering plant in the family Asteraceae. It is widespread through much of the United States and Canada. It is the only species of the genus Eutrochium found west of the Great Plains. This herbaceous perennial sometimes grows as high as 2 m (6 ft 7 in). Stems are sometimes completely purple, sometimes green with purple spots. One plant can produce numerous rose-purple flower heads in late summer, each head with 8-22 disc flowers but no ray flowers. The specific name maculatum, meaning spotted, refers to the purple spots on the stem. Spotted Joe Pye weed thrives in marshes, rich fens and swamps. It also does well in man-made moist expanses such as ditches, seepage areas and wet fields. Above all else the plant flourishes in the non-shaded environments that are also abundant in wetlands. It is a larval host to the Clymene moth, the eupatorium borer moth, the ruby tiger moth, and the three-lined flower moth.......read more on Wikipedia.