Signs along Lougheed Highway warn locals that an invasive species is being treated.

Japanese knotweed, a highly invasive plant, is being targeted along the highway but it has also invaded watershed and streams in Maple Ridge.

Knotweed is especially harmful because it can crack through concrete and asphalt, for example, through roads and retaining walls.

The Invasive Species Council of Metro Vancouver has been tasked with getting rid of knotweed in both Kanaka Creek Regional Park - a Metro Vancouver park - and along the Lougheed Highway, which falls under the provincial Ministry of Transportation and Infrastructure.

Jennifer Grenz, development and projects manager with the Invasive Species Council of Metro Vancouver, said the herbicide treatment is "very, very targeted," and vegetation farther away from area won't be affected by the treatment.

"The treatment methods are very specific," Grenz said.

The spraying along the Lougheed Highway west of 216th Street was done late last week, and Grenz pointed out plants would take a few weeks to die.

A large-scale treatment was done in Kanaka Creek Regional Park in June and last week the invasive species council was back monitoring how well the treatment had gone.

The Japanese knotweed is native to eastern Asia.

According to the invasive species council, knotweed can grow up to three metres per year and can degrade wildlife and fish habitats.

The root systems are extensive and they can resprout after several years of control measures.

The roots can also break off and float and form new infestations downstream.

Geoff Clayton, spokesperson for the Alouette River Management Society, called knotweed "a sleeping giant."

"We've found a lot of the watersheds and creeks are being choked [in Maple Ridge]," Clayton said.

And the problem is getting worse, he added.

ARMS has been in discussion with the District of Maple Ridge, parks and leisure services, and Metro Vancouver about the issue.

ARMS would like to see computer maps made of where knotweed exists.

"Like any enemy, first you have to determine the force coming against you," Clayton said.

After they know how much knotweed they're dealing with, they need to use "best science" and determine how to combat it, he added.

Fred Armstrong, communications manager with the District of Maple Ridge, pointed out that it is one of a number of problematic invasive plants in the District.

Armstrong said the problem of knotweed has been identified by the District and a plan is being worked on.

For more information, call 1-888-BCWEEDS.

Or check the Invasive Species Council of B.C. website at www.bcinvasives.ca. or the Invasive Species Council of Metro Vancouver's website at www.ipcmv.ca.

mrantanen@mrtimes.com