Knotweed Update

August 21, 2016

Bohemian Knotweed (a hybrid between Japanese and Giant Knotweed) has been documented at the Riverview Lands. One of the world’s most invasive plants, knotweed has the ability to cause significant damage to building infrastructure and has considerable ecological effects.

In BC, knotweed is classified as a “Noxious Weed.” Under this designation, the owner of the property has a legal responsibility to control it.

To protect the grounds, BC Housing is working with specialists in invasive species management. The contractor that BC Housing has tasked to execute this project discussed treatment with the City of Coquitlam, to determine the most appropriate course of action to ensure every possible protection of the environment, together with the plant and wildlife that resides within in it.

As knotweed is resilient to mere cutting, a pesticide was applied to control its growth. The site was treated twice; once on July 13 and once on August 11. Large stemmed plants were cut down and carefully treated with glyphosate dimenthylamine on the stems. Small stemmed plants were treated by applying a 5% active ingredient solution of glyphosate to the plant leaves. Small stemmed plants close to other native plants were treated by painting individual leaves with undiluted glyphosate.

This method is the most environmentally sound solution for the treatment of knotweed. Pesticide notices were posted on the Riverview Lands following treatment. All Federal, Provincial and Municipal regulations have been followed.