QuestionsHow to growTrees and ShrubsWeedsIdentification of broadleaf weed. 0 Vote Up Vote Down James Begley asked 13 years ago Please identify from the attached picture. Can grow very tall. Also recommend how to eradicate. 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 6 years ago That is Japanese knotweed, a pernicious weed that was once a garden flower. Roundup used repeatedly will give control.