Ohrn Image — Arbutus Greenway In Late October I

Another great photo by Ken!
One thing that really stands out in this photo is the huge patch of Japanese knotweed. It seems innocuous and quite beautiful (often mistaken for bamboo) until you realize that it’s the Godzilla of invasive plant species with no known predators here. The roots can penetrate 5m or more into the ground, and travel 10m horizontally under the surface to pop up and form another clump. This plant can split bridge abutments, break foundations and can grown through your basement floor slab. Further, the plant goes into overdrive when cut, mown or otherwise disturbed, and these activities are key to its quick spread. Even a small leaf fragment stuck to a mower can root km away when it drops to the ground. The mowing by the CPR and deposits of organics onto the site from the lawns and gardens in the neighbourhood are the likely vectors of its spread.
It’s a huge issue in the Lower Mainland now. The only known effective way to deal with it is, unfortunately, with powerful systemic herbicide, like RoundUp which, when sprayed to the leaves carries a toxin to the bottoms of the roots. The plant is now building up a resistance to herbicids. Most cities are using special dig-and-spray techniques by experienced companies to deal with it, and it isn’t cheap. The soil and plant material has to be incinerated or put into the deep burial (with cap) sections of some of the landfills. All the equipment used by treatment personnel needs to be washed and the waste water disposed of accordingly.
Beware this beauty … it’s really a beast.