Invasive weeds threaten northwest

Bob Drinkwater holds Japanese knotwood, an invasive plant he says endangers local eco-systems - STAFF PHOTO
Bob Drinkwater holds Japanese knotwood, an invasive plant he says endangers local eco-systems
— image credit: STAFF PHOTO

PLANTS IMPORTED for their looks in gardens and yards are now causing big problems in the northwest.

Species such as Dalmatian Toadflax, Tansy and Yellow archangel threaten native plants and, indirectly, wildlife and fish, says Bob Drinkwater from the Northwest Invasive Plant Council.

“Without the natural ways to control them where they come from, such as insects, when they get here they grow out of control,” he said.

Some alien plants will choke out natural plant food sources for animals. But what has Drinkwater particularly worried in this area is Japanese knotwood, a bamboo-like plant which loves to grow along stream and creek banks.

It’s a perennial which spreads to become thick and dense cover, killing off natives species, says Drinkwater.

“It can completely dominate an area,” he said of the plant.

“And because it has a poorly developed root structure, the bank will fall away into the water, causing the stream bed to silt up and that will ruin spawning beds.”

And as the silt washes downstream, the knotweed floats with the current and can establish itself elsewhere.

“What you have to do then is eradicate the knotweed and follow it all the way back to where it started,”  said Drinkwater.

An infestation of knotweed was found in the New Remo area several years ago and there’s quite a bit of it within Terrace.

“It can grow to seven feet tall it has a staggered leaf pattern,” said Drinkwater. “If not stopped, it will have a huge impact on the salmon population.”

The Northwest Invasive Plant Council is a non-profit group made up of public and private sector groups and financed by the public and private sector. Crews travel throughout the region identifying and dealing with alien plant species.

Tracking plant growth and progress has turned into a hi-tech affair with locations now recorded on maps via GPS coordinates.

For more information call, toll-free,1-866-44WEEDS (449-3337) or visit


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