This weedy plant stood at least 10 feet tall.
Clinton County, Illinois, US
along a creek. Most were very tall (8-10ft). I chose one of the smaller guys to photo.
Vernonia gigantea (also known as Giant ironweed, Tall Ironweed or Ironweed) is a species of perennial plant from Asteraceae family that can be found in United States and Canada. The plant is native to the eastern United States, north to New York state and Ontario, and southwest to Texas.