Reynoutria ×bohemica

Growing from 6 to 12 feet tall, giant knotweed prefers disturbed areas such as fields, pastures and roadsides.  Tiny white to pink flowers can be found between July and October. Giant knotweed is prohibited in New York; it is illegal to purchase, sell, transport or propagate. (Reynoutria japonica × R. sachalinensis = R. ×bohemica, a common naturally occurring hybrid)