Know what you grow: Knotweed an invasive species

Knotweed rapidly invades shoreline, river-bank, and stream-bank habitats, where it blocks sunlight.

Knotweed rapidly invades shoreline, river-bank, and stream-bank habitats, where it blocks sunlight, disturbs nutrient cycling, displaces native vegetation, and increases stream-bank erosion. Try these instead: Goats Beard (Aruncus dioicus), Black Elderberry (Sambucus racemosa var. melanocarpa), and Oceanspray (Halodiscus discolor).

In the coming weeks, Knotweed plants that have spread their roots and stems over the last few months will begin producing delicate white flowers throughout the region. Be sure to know how to identify the Knotweed varieties in our area to help stop the spread of these invasive plants.

There are four different species of knotweed infesting British Columbia; Japanese, Himalayan, Bohemian, and Giant Knotweed. These bamboo-like plants, have become one of the most prolific invasive plants in the world with serious infestations in the United Kingdom, United States of America, and even here in Canada. In fact, stiff regulations and policies have been developed within the United Kingdom to help address their Knotweed issues.

Within the Cariboo Regional District (CRD), Knotweed is a regulated plant species under the BC Weed Control Act and the CRD’s Invasive Plant Management Regulation Bylaw.

Knotweed has the ability to spread very quickly because of its extensive root system which can reach 15–20 metres in length. Growth of new shoots can emerge up to 20 metres away from the parental plant and when disturbed, a hormone in the plant is released stimulating the growth of new shoots.

Knotweed spreads predominantly through a creeping root system; however it can also spread by seed. It can grow from one to five metres tall and crowds out native plants and habitat. Young shoots generally begin to emerge in May and growth rates of eight centimetres per day have been recorded. Knotweed has been observed to grow in environments without sunlight, through building foundations and through five centimetres of asphalt. It is a huge threat to species diversity and wildlife habitat.

Knotweed is no longer sold in nurseries, but is still spread through the sharing of garden plants, contaminated soil, and root fragments drifting downstream in water.

Knotweed has been found throughout the Cariboo Chilcotin and mostly in gardens, but recently many new plant sites have been found in unauthorized garden waste dump sites.

To keep this species from causing widespread impacts in the region, it is important to prevent its establishment in the first place. Do not purchase, trade, or grow Knotweed as there are better alternatives available including native plant species.

If you have Knotweed growing in your garden it is important to care for it in a manner that is not going to cause further spread.

Be sure to phone the Cariboo Regional District for advice on treating and disposing knotweed to ensure it is handled correctly.

If you have any questions or concerns about Knotweed or need some assistance in identification or management, please contact the CRD’s Invasive Plant Management department at 250-392-3351, or toll free at 1-800-665-1636, or visit our website at or on Facebook at

Just Posted

Michelle Jacobs receives her first dose of the COVID-19 vaccine at the Coast Capri Hotel on April 28, 2021. The pop-up clinic was hosted by the First Nations Health Authority. (Aaron Hemens/Capital News)
126 new cases of COVID-19 in Interior Health over the weekend

There are 22 individuals hospitalized due to the virus, and 13 in intensive care

A Cariboo Regional District director and School District 27 trustee, Angie Delainey is also a fourth generation business owner in downtown Williams Lake. (Angie Mindus photo - Williams Lake Tribune)
Angie Delainey appointed Cariboo Regional District representative on regional board

Delainey and Steve Forseth represent the CRD at the North Central Local Government Association

Pauline Schmutz, 75, receives her COVID-19 vaccine from public health nurse Donna McKenzie on Tuesday, April 13 at the community clinic at Thompson Rivers University Williams Lake campus. (Monica Lamb-Yorski photo - Williams Lake Tribune)
Additional COVID-19 vaccine clinics scheduled for Horsefly, Big Lake

Anyone 18 and over who has not received a vaccine yet is encouraged to register

The Cariboo Regional District. (Angie Mindus photo)
Industrial park slated for Watch Lake Road

Building company Omnitek to start building new plant on 32-acre site

Kokanee Bay Fishing Resort on Puntzi Lake has been purchased by Tsideldel First Nation. (Kokanee Bay Fishing Resort photo)
Tsideldel First Nation buys Kokanee Bay Fishing Resort at Puntzi Lake

“It’s a good opportunity for the band, our children and our future,” said Chief Otis Guichon

An avalanche near Highway 1 in Glacier National Park. Avalanche Canada will benefit from a $10 million grant from the B.C. government. (Photo by Parks Canada)
Avalanche Canada receives $10-million grant from B.C. government

Long sought-after funds to bolster organization’s important work

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

Sicamous RCMP Sgt. Murray McNeil and Cpl. Wade Fisher present seven-year-old Cody Krabbendam of Ranchero with an award for bravery on July 22, 2020. (Contributed)
7-year old Shuswap boy receives medal of bravery for rescuing child at beach

Last summer Cody Krabbendam jumped into the lake to save another boy from drowning

B.C. Health Minister Adrian Dix and provincial health officer Dr. Bonnie Henry update the province’s COVID-19 vaccine program, May 10, 2021. (B.C. government)
B.C.’s COVID-19 infection rate stays below 500 a day over weekend

14 more deaths, down to 350 in hospital as of Monday

Royal Bay Secondary School’s rainbow crosswalk was vandalized shortly after being painted but by Monday, coincidentally the International Day Against Homophobia, Transphobia and Biphobia, the crosswalk had been cleaned up and students had surrounded it with chalk messages of support and celebration. (Zoe Ducklow/News Staff)
B.C. high’s school’s pride crosswalk restored following ‘hateful’ graffiti attack

Hate terms, racial slur, phallic images spray-painted at Greater Victoria high school

Terrance Mack would have celebrated his 34th birthday on May 13, 2021. Mack’s family has identified him as the victim of a homicide in an apartment on Third Avenue in Port Alberni sometime in April. (SUBMITTED PHOTO)
Family identifies Ucluelet man as victim of Vancouver Island homicide

Terrance Mack being remembered as ‘kind, gentle’ man

Vancouver Canucks’ Jake Virtanen (18) and Calgary Flames’ Josh Leivo, front right, vie for the puck as goalie Jacob Markstrom, back left, watches during the first period of an NHL hockey game in Vancouver, on Saturday, February 13, 2021. THE CANADIAN PRESS/Darryl Dyck
Vancouver Canucks forward Jake Virtanen sued over alleged sexual assault

Statement of claim says the woman, identified only by her initials, suffered physical and emotional damages

An avalanche near Highway 1 in Glacier National Park. Avalanche Canada will benefit from a $10 million grant from the B.C. government. (Photo by Parks Canada)
Avalanche Canada receives $10-million grant from B.C. government

Long sought-after funds to bolster organization’s important work

Daily confirmed COVID-19 cases reported to B.C. public health, seven-day rolling average in white, to May 12, 2021. (B.C. Centre for Disease Control)
B.C. preparing ‘Restart 2.0’ from COVID-19 as June approaches

Daily infections fall below 500 Friday, down to 387 in hospital

Most Read