Japanese knotweed is listed by the International Union for Conservation of Nature as one of the world’s 100 worst invasive species. Often mistaken for bamboo, this tall and pretty plant is fast-growing (six centimetres per day) and requires minimal care.
The extensive root system can grow through foundations, damage concrete walls, pavement, drainage works, and flood prevention structures, resulting in expensive problems for both the city and private landowners.
Knotweed is notoriously difficult to eradicate, and studies around the world have repeatedly shown that mechanical efforts such as cutting, digging, smothering, or burning are ineffective and can contribute to its spread. The current best practice is spot-application of a selected non-glyphosate herbicide by a licensed contractor. There are a lot of resources to learn more about knotweed online. For example, the Ontario Invasive Plant Council.
For a quick summary of invasive plants in Kitchener, watch this presentation to Kitchener city council, from August 2019.
by Kathy M.