Invasive Species Council of British Columbia

StrongerBC Action Teams Help Tackle Yellow flag iris Invasion in Chilliwack 

SBC Action Teams paddling in Bell Slough

By Fiona McDonald | July 21st, 2022

What do 732 bananas, 1,407,059 bees, and 35,365 tea bags have in common? They’d all weigh approximately 242 lbs, the same amount of Yellow flag iris (Iris pseudacorus) seed heads that were recently removed from Bell Slough in Chilliwack! 

ISCBC’s StrongerBC Abbotsford and Metro Vancouver Action Teams recently joined up with Watershed Watch Salmon Society and Fraser Valley Invasive Species Society to tackle this Yellow flag iris invasion.  

So, why is Yellow flag iris a problem? 

Yellow flag iris invades ditches, wetlands, streams, lake shorelines, and shallow ponds. It’s a speedy spreader through seed dispersal, a horizontal root system, and its ability to grow from just a piece of the root, so it can take over an ecosystem very quickly and aggressively.  

Several hundreds of plants may be connected underwater due to the extensive root system, which creates a thick mat that damages wildlife habitat, reduces water flow, and crowds out native vegetation. 

How can you identify a Yellow flag iris? 

The flowers of this iris are bright yellow, often with brown spots or purple veins, with 3 upward pointing petals and three downward pointing, tongue shaped “petals”, called sepals. The flowers appear on a smooth stem about 100-150 cm tall and the leaves are flat and sword-shaped, up to 90 cm long and 3 cm wide. 

Yellow flag iris (Iris pseudacorus) | Credit: L Scott

Many hands make light work.  

Well, maybe 242 lbs isn’t that light. By working together, staff, volunteers, and our friends at Watershed Watch Salmon Society and Fraser Valley Invasive Species Society were able to make space for restoration of the natural habitat to begin.  

“Spending my summer days kayaking and removing invasive species in a sensitive area, helping set the Chilliwack sloughs on a upward trajectory to restoration was an amazing experience, and being able to help and connect with local stewardship groups was an amazing opportunity. I look forward to see what the slough will look like with continued work.” — Torin Kelly – Abbotsford Action Team supervisor. 

“I had an amazing time helping out with removing Yellow flag iris from Bell Slough. It was a pleasure to be out with the community to try and help make a difference.”  — Katie Poustie – Abbotsford Action Team member.

“We are so excited to support the work that Friends of Bell Slough have been doin! Through their positive energy and forward motion they are restoring hop to the Bell Slough one event at a time. Thank you ISCBC for supporting our Yellow flag iris clipping day and supporting this community project!” — Watershed Watch Salmon Society

“The Friends of Bell Slough have been making leaps and bounds to improve this waterway in Chilliwack. FVISS is so glad to have the StrongerBC Team join us in supporting their efforts and managing the spread of invasive Yellow flag iris!” — Fraser Valley Invasive Species Society

SBC Action Team Members on the water in Bell Slough

ISCBC is grateful to the StrongerBC funding from the Province of BC that supports individuals in training and providing work for people whose jobs were impacted by the COVID 19 pandemic and to help protect BC’s lands and waters from invasive species. 

Fiona McDonald is a Communications Coordinator with ISCBC and primarily manages our social media accounts. She is an avid birder, nature photographer, and can usually be found outside making fun, educational nature content to share her love of the outdoors with everyone. You can reach Fiona at or find her on TikTok @bcinvasives