Japanese knotweed is an invasive species of plant that was first introduced to the United States from Japan in the late 1800s. It is also known as fleeceflower, huzhang, Mexican bamboo, Hancock's curse, monkeyweed or by its scientific name, Fallopia japonica.
The World Conservation Union considers Japanese knotweed one of the most invasive plant species in the world. It grows quickly, forms dense colonies that crowd out other species, tolerates a wide range of weather and soil types, and is resistant to cutting. Its roots have been known to damage sidewalks, roads, concrete foundations and retaining walls. The use of herbicides is the most effective way to control its spread.