Giant Knotweed is a truly vicious invasive species. They can grow in a variety of different areas, including but not limited to riverbanks and roadsides. Giant Knotweed will look like bamboo on its stem but have large teardrop shape leaves. The plant will sometimes stretch 16-17 feet in some areas. Giant Knotweed is part of a group that is called the Noxious Weeds. Noxious Weeds are weeds that harm ecosystems, habitats, livestock, humans, and crops. Giant Knotweed is very close to the Japanese Knotweed in DNA, so it can inter pollinate and produce an invasive hybrid. Both the Giant Knotweed, the Japanese Knotweed, and the hybrid are in the group of Noxious Weeds.