CRD weed of the week the Yellow Flag Iris

Gardeners should be aware that the Yellow Flag Iris, while a beautiful exotic aquatic water plant, is a serious invasive species.

Gardeners should be aware that the Yellow Flag Iris, while a beautiful exotic aquatic water plant,  is a serious invasive species, reports the Cariboo Regional District.

This plant is native to Europe, the British Isles, North Africa and the Mediterranean region.

And as of right now, it is still being sold in nurseries and can be bought on the Internet, around the world.

Yellow Flag Iris grows about four feet tall with a robust stalk and the stems/leaves are long, dark green, flattened and sword like.

The leaves have a distinctive ridge in the mid-vein and they contain a sap that is toxic if ingested or can cause skin irritations.

The flowers are a vibrant yellow with three petals that are backwards curving. What makes this plant multiply so quickly, is that it spreads vegetatively and by seed.

If a piece of the roots breaks off, the piece is able to float down stream and re-sprout a new plant.

The seed pods of yellow flag can remain buoyant in the water for up to seven months.

Yellow Flag Iris can grow in a variety of different habitats including dry, high acidy or anoxia soils, brackish waters and in fresh or salt water.

It can be found in temperate wetland, along margins of lakes, ponds, ditches and slow moving rivers.

This invasive species is a major problem for aquatic habitat because of its ability to colonize so quickly and the roots form dense mats that are up to 30cm deep which choke-out much of the native vegetation.

Since it can form dense stands, it can change the width of water courses by compacting soil trapping sediments and increasing elevation.

It also affects the water flow of irrigation canals and flood control ditches.

There are Yellow Flag Iris infestations in Williams Lake that are currently being treated and recently the CRD Invasive Plant crews have inventoried new infestations along the shoreline of Lac La Hache.

Treatment options for Yellow Flag Iris are:

• Hand pulling by digging up the whole plant making sure you dig up the entire root and any fragments.

• Cutting the plants right to ground level, this will have to be done several times but can be affective.

All plant material must be bagged and disposed of in designated areas, such as invasive plant bins at your local landfill.

Do not compost invasive plants.

To stop the spread of Yellow Flag Iris:

1.) Learn to identify this aquatic exotic.

2.) Do not purchase and plant Yellow Flag Iris.

3.) Wash boats and other water recreation vehicles before leaving a lake.

4.) Minimize soil disturbance.

5.) Report any sightings to the CRD at 1-800-665-1636, online at or email

Instead of planting Yellow Flag Iris in your garden try these alternatives: Japanese Iris (Iris nsata), Siberian Iris (Iris Sibirica) or Laevigata Iris (Iris laevigata).


Just Posted

Bella Coola Valley. (Scott Carrier photo)
Nuxalk Nation closes recreation, sports fisheries at Bella Coola due to COVID-19 concerns

Nobody is supposed to be travelling, said marine use manager Peter Siwallace

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

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

The top photo is of a real carbine rifle, while the bottom photo is the airsoft rifle seized from a Kelowna man on May 15. (Contributed)
RCMP issue warning: ‘Imitation firearms need to be dealt with responsibly’

A man brandishing his airsoft rifle in public had his weapon seized by Mounties on Saturday

Abbotsford Regional Hospital. (Black Press Media files)
Canada marks 25,000 COVID-19 deaths since the pandemic began

6 in every 10,000 Canadians died of COVID-19 since March 9, 2020

Relief is coming for B.C.’s struggling tourism sector. (NEWS file photo)
B.C. officials set to announce more support for tourism sector hit hard by pandemic

Non-essential travel is restricted between three regional zones in B.C. until at least May 24

This image released by Universal Pictures shows Nathalie Emmanuel, left, and Vin Diesel in a scene from “F9.” (Giles Keyte/Universal Pictures via AP)
The blockbuster movie is making a comeback this summer

Excitement in the industry is growing again for a return to a big-screen normal

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

Most Read