British Columbia

Invasive Japanese knotweed takes root in Burnaby

Foreign weed can push its way through tarmac roads and concrete building foundations

Posted: October 15, 2015

Burnaby, B.C. officials are struggling to get rid of Japanese knotweed, a stubborn foreign weed that can push its way through tarmac roads and concrete building foundations.

The powerful weed can expand to cover almost half a hectare and grows back from the roots every year. Experts say digging it up only causes the roots to multiply, so they recommend professional herbicides instead.

But Melinda Yong, Environmental Coordinator for Parks, says herbicides haven't been the answer for the City of Burnaby.

"Our limitation is that the herbicides that are available for us to use, we cannot use them within the one-metre high water mark of a water body," said Yong.

"So areas like creeks, ravines, rivers ... we aren't able to treat the Japanese knotweed so that's a big limitation for us.

Yong says an audit by the parks department found the invasive plant species was present in about 20 per cent of Burnaby's park space.

Can affect property values

According to Mark Haywood, with Britain's National Association of Estate Agents, Japanese knotweed has been wreaking havoc in Britain for years and can actually bring down property values.

"What occurs is the person trying to sell the property has no knotweed on their property but it's growing from an adjoining property into theirs," Haywood told CBC Radio's The Current earlier this year.

"They can't sell their property and may approach the neighbour to help pay for it to be eradicated," he said. 

With files from Kirk Williams