Yellow-Flag Iris in the Clayoquot & Barkley Sound Region

Yellow-flag Iris (Iris pseudacorus) originates in Eurasia but is an invasive flowering plant that thrives in various habitats worldwide. Sometimes it is also referred to as Water Flag Iris or Yellow Iris.

They invade ditches, wetlands, streams, lake shorelines, and shallow ponds. While invading these ecosystems, the plants damage local species and the environment as a whole.

Yellow-flag Iris is a deadly combination of being quick spreading and incredibly difficult to remove.

This plant has bright yellow flowers, with three petals pointing up and three pointing down, and grows to be around 100-150cm tall. They have large flat green leaves and bright pink creeping rootstalk (rhizomes).

Many landowners plant this flower for its looks without realizing its toxicity and the damage it does to the wetlands it occupies. This StoryMap will explore the impacts of invasive species on the West Coast and what you can do to help.

The study areas referenced in this article are situated on the traditional territories of the Tla-o-qui-aht and Yuułuʔiłʔatḥ Nations, who have stewarded the lands for thousands of years. These territories encompass the towns of Tofino and Ucluelet and the coastline in between.

The Clayoquot & Barkley Sound Region is home to a  variety of ecosystems . Click on the points to learn more about the diverse ecosystems the Yellow-flag Iris threatens!

Removing Yellow-flag Iris early can prevent problems in your garden and protect your local environment.

Manual removal of these plants is recommended; however, this endeavour can be labour-intensive due to the extensive rooting system of the Yellow-flag Iris. When removing Yellow-flag Iris, it is essential to remove all subterranean rhizomes and material. There is evidence that even the smallest of pink fragments can regrow. All materials should be appropriately disposed of.  Click here  for more removal information.

One of the treatment and removal techniques being trialed in Ucluelet, BC, is the implementation of  benthic barriers . This technique utilizes a weighed-down tarp to suffocate the roots of the plants under the water table. Cutting plants to the ground, then covering them with a benthic barrier deprives the Yellow-flag Iris of light and oxygen. The barrier prevents the now cut-down plants from diffusing the toxic metabolic byproduct acetaldehyde, resulting in plant suffocation and cell die-off. This effectively kills the plant and leaves only the weak rhizomes to pull. In contrast to needing a pickaxe to get through the tough root mats.

Once the benthic barriers are removed, the patches can be tackled. On the left is an untreated patch; note the ground cover, new shoots, and thick matting. On the right is a treated patch with no sprouting or matting, displaying exposed rhizomes. The theory is that the treated patch will be easier to remove.

The research efforts of organizations across British Columbia are essential in restoring wetland ecosystems to their original functions. However, there is so much you can do as an individual to help!

The first step to dealing with an invasive species is prevention. Don't plant Yellow-flag Iris because its multiple reproduction systems will take over your garden and surrounding ecosystems. Many other beautiful plants would make a great addition to your garden without destroying local ecosystems. Check out this  "what to plant" guide , or ask your local garden center about native plants!

By removing Yellow-flag Iris from your property, you are preventing the spread of this invasive plant. Use the navigation bar to return to our removal section if you have this plant in your garden! You can also get involved by volunteering to help out when community organizations hold events to eradicate patches in public areas.

Research projects like this one often rely on citizen science! You can get involved by documenting Yellow-flag Iris on  iNaturalist  or with the  Invasive Species Council of BC  when you see it.

The  Wetland Stewards for Clayoquot & Barkley Sound  and  Redd Fish Restoration Society  are working together to pioneer Yellow-flag iris removal and habitat conservation efforts. You can follow their Facebook Pages for regular updates regarding potential volunteer opportunities, and regardless of where you are located, you can donate to their charities by clicking below!