Knotweed is an herbaceous perennial plant that is highly invasive in North America. Knotweed forms white flowers from late summer to early autumn. The stems are hollow (similar to bamboo shoots) and the leaves grow in a zig-zag pattern. Most varieties have leaves that are either triangle or heart-shaped. 

 In the spring, new shoots begin to grow through the soil. They are generally dark red and green and look similar to asparagus spears. On new emerging shoots, the leaves are rolled up and they unravel as the plant continues to grow in height.

To learn more about how to identify knotweed, please refer to our blog post here.

Knotweed is extremely aggressive, and it can even grow through concrete if not managed.  It is a homeowner’s responsibility to ensure knotweed on their property does not spread into the wild or onto a neighbour’s property. It is recommended to treat knotweed as soon as you are aware of it. With more time spent growing, knotweed becomes more established which makes it more difficult to eradicate.

Management methods such as mowing, digging, and pulling are considered ineffective methods of removal. Knotweed has a large underground root system made up of a network of rhizomes.

Attempting to pull or dig the knotweed out of the ground may encourage growth, and mowing over a patch of knotweed can spread it to surrounding areas.

The most effective method of management for knotweed is a glyphosate herbicide. Keep in mind that knotweed growing near waterways cannot be treated with unlicenced herbicide.

If in the Fraser Valley, contact the Fraser Valley Invasive Species Society (FVISS). Their website can be found here, and they have a page devoted to invasive plant management contractors here.

If you are elsewhere in southwest BC, contact one of our partners here.

If you are located elsewhere, look for similar invasive species organizations in your geographic area.