Eutrochium maculatum (spotted joe-pyeweed is a North American species of flowering plants in the sunflower family. It is widespread through much of the United States and Canada. It is the only species of the genus found west of the Great Plains.
Eutrochium maculatum is an herbaceous perennial sometimes growing as high as 2 m. 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 binomial 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 (source Wikipedia).
This Picture is made in an Ornamental Garden in the Netherlands.