Several residents have confused Himalayan Balsam with Japanese knotweed
The plant on the left is Himalayan Balsam and that on the right is Japanese knotweed.
Flower colour is the easiest determinant.
Himalayan Balsam is an annual growing each year from seed, whereas Japanese knotweed is a perennial. Both are very invasive.
Given the confusion, this website has been updated with information on how to control Himalayan Balsam.