what is knotweed plant
Japanese Knotweed is an aggressive semi-woody perennial plant that is native to eastern Asia. In the 1800's it was introduced to North America as an ornamental species and also planted for erosion control.It has since spread throughout the United States and Canada.mpacts of Japanese Knotweed. 1  Spreads quickly, creating dense thickets that degrade wildlife habitats. 2  Reduces plant biodiversity by competing with other native vegetation. 3  Aggressive plant with a strong root system that has been known to break through asphalt and concrete. 4  Plant populations are extremely persistent. 5  It can establish along ...