Knotweed beware

Gardeners and homeowners in the Okanagan are being asked to keep a wary eye out for Japanese knotweed, an invasive plant that is of growing concern.

“It's one of the weeds that seems to have been transplanted at some point in time in B.C. as people brought it in as a landscape plant,” said Clint Kanester, City of Vernon bylaw compliance manager.

The plant is attracted to moisture and grows from one to five metres tall. Attractive when in bloom, the Japanese knotweed has heart-shaped leaves, delicate white flowers and thick, bamboo-like stems.

“Every little piece of it will start to grow and will start to grow a new plant,” warned Kanester, who's department must enforce the Weed Control Act within Vernon. It is listed as a noxious weed by the province.

While Kanester said the plant is fairly new to the Okanagan area “it has the potential to have a huge impact within different ecological areas within B.C.”

Gardeners are warned that Japanese knotweed knows no limits.

“It takes over from existing vegetation so it will start to spread, it will start to clump and will create large areas where it will take over from the native vegetation.”

The roots and stems are so strong, said Kanester, that the plant can affect a home.

“It will actually break through concrete,” he said. “It's like a nasty dandelion that grows up in your asphalt driveway.

“It will keep coming back because it grows under the ground but it is strong enough so that it will actually push up through concrete or create problems with foundations if it is up against the sides of houses.”

So far, around eight to ten cases of knotweed have been reported, according to bylaw.

People are being urged to look for the plant in their yards and to root it out.