Japanese knotweed is a highly invasive species seen in many areas of Prince Rupert. The city has already started spraying herbicides to stem the problem.

City declares war on Japanese knotweed

Prince Rupert began spraying herbicides in an effort to eradicate the highly-invasive Japanese knotweed that has sprung up in the city.

The City of Prince Rupert has started tackling the growth of Japanese knotweed, as more and more of the highly-invasive plant is sprouting up within the community.

Japanese knotweed is considered to be one of the world’s most invasive plant species, having a deep, strong-rooted system that can cause significant damage to concrete foundations, buildings, retaining walls, roads, as well as water and sewer lines.

To address the issue, the city has hired the Spectrum Resource Group to treat city-owned properties where knotweed is growing.

“The city has already completed a round of treatment … Knotweed generally takes more than one round of treatment to be successful,” said Veronika Stewart, communication manager of the city.

“Thankfully, it is relatively inexpensive, and we have been able to identify a professional that will treat in our area through coordination with the Northwest Invasive Plant Council.”

The city will continue paying for herbicides to be sprayed on public lands, however Prince Rupert residents and business owners are responsible for treating knotweed on their properties.

The plant is characterized by its triangular-shaped leaves and long stems, which resemble bamboo or rhubarb because of its round-hollow stalks.

RELATED: KNOTWEED INVADING CITY AND RESIDENTIAL LAND

Knotweed can quickly grow several metres, easily spreading over property lines. The city recommends private land owners hire professionals to treat knotweed growth, as it’s resilient and will re-sprout vigorously if chopped down.

The most effective method of controlling growth is to apply the herbicides glyphosate (known as “Roudup”), imazapyr, or a combination of both, with a number of applications being required to fully eradicate the plant. It usually takes two to five years to accomplish the complete annihilation of knotweed.

To combat Japanese knotweed plants, residents are encouraged to contact Spectrum Resource Group Inc. at (250) 596-8783. The cost of treatment may vary, with an average sized area costing about $50 to treat.

Furthermore, the city is asking residents to report any knotweed growth for its knotweed community inventory. Individuals can report the growth of plants on the City of Prince Rupert website at http://www.princerupert.ca/community/online-forms/knotweed