Japanese Knotweed: invasive plant species

Japanese Knotweed (lat. Fallopia japonica), identified in Westmount, is considered one of the most invasive and persistant plants. This perennial of Asian origin has been used in Canada as an ornamental and to control erosion.

Although often mistaken for bamboo because of its appearance, Japanese Knotweed has the following characteristics:

  • large oval leaves (3-6 inches long and 2-5 inches wide)
  • round, reddish-purple hollow stems with bamboo-like knots
  • very rapid growth, reaching between 1 and 3 metres in height
  • small, greenish-white flowers that produce a small white fruit with wings that help disperse seeds
  • brown, shiny seeds
  • resistance to Canadian winters.

Find out more

Once established, it is very difficult to get rid of Japanese Knotweed. Consult our invasive plants page to learn how to identify the plant, prevent it from propagating, and eradicate it.

Report its presence in public spaces

If you see Japanese Knotweed anywhere in Westmount’s parks and public green spaces, please report it to the Public Works Department by using the Contact Us form, or by phoning 514 989-5213.