It’s a weed that can push through four feet of concrete and spread like kudzu—and British Columbia is dead set on eradicating it before it threatens the region’s infrastructure.
The scourge is invasive knotweed, and the threat is no joke: The Canadian province calls knotweed “one of the world’s worst invaders” and has mounted a multi-jurisdictional effort aimed at rooting it out.
Invasive Species Council of Metro Vancouver
|Japanese Knotweed can force its way through asphalt, concrete and metal.|
The weed can push through asphalt, concrete and even metal, breaking up roads, pavement, drainage systems, highways, foundations, and other structures.
Worse, the hardy plant can grow and flourish from the smallest stem fragment. And attacking the plant by digging and cutting can actually cause it to spread.
Three species of knotweed, sometimes called ornamental bamboo, have now been found in British Columbia.
British Columbia has thrown a one-two punch at knotweed in recent weeks and is now warning the construction industry about the weed, which can drive up project costs and “unleash chaos on a contractor’s guarantee,” as Canada’s Journal of Commerce recently reported.
Last week, the Capital Region Invasive Species Partnership (CRISP), which includes British Columbia’s local governments and land managers, unveiled a new regional reporting system for knotweed. The Partnership, formed in 2010, called on area residents to “be on the alert for invasive knotweed and report any sightings through [the] regional reporting system.”
That alert followed the recent addition of four species of knotweed to British Columbia’s Weed Control Act, which requires landowners to eradicate the invasive species.
For more information or to make a report, visit www.coastalinvasiveplants.com or call 250-857-2472.
‘Already Too Late’
“In neighboring regions, it is already too late,” warns Becky Brown, Invasive Plant Specialist for BC’s Ministry of Forests, Lands and Natural Resource Operation. “These plants are capable of growing through four feet of concrete and can reproduce from a fragment no larger than the size of your small fingernail.”
Brown said the weed had already damaged infrastructure in neighboring regions.
|A report prepared for the Millard/Piercy Watershed Stewards described a study that dispatched a detail of nature’s supreme mowers—goats—to attack the noxious knotweed. The results were promising.|
In the UK, knotweed has been designated “controlled waste,” and “some financial institutions will not grant mortgages on contaminated lands,” Brown said. “It is only a matter of time in British Columbia.”
Focus on Contractors
The region is trying to warn contractors about the threats posed by the weed.
“We are trying to get the word out to the construction industry,” said Jennifer Grenz, program manager for the Invasive Species Council of Metro Vancouver. Contractors for the London Summer Olympics’ velodrome and aquatic centers were plagued by knotweed, Grenz said.
Land managers have “an incredible and limited opportunity to eradicate” knotweed, Brown said. The effort requires the public’s help, authorities said.
Area residents are being asked to call the reporting system for treatment and disposal assistance. "Treatment of this species is very difficult, so a regional response has been set up,” CRISP noted.
The agency "appreciates the cooperation of all residents in addressing knotweed on private property with the assistance of local professionals.”
“This is a unique species requiring special treatment.”