Connect with us

Report an Invasive Species

Yellow flag-iris

Yellow flag-iris

Yellow flag-iris

(Iris pseudacorus)

Priority: -  Contain

Tags: Aquatic | Toxic



Perennial herb that grows in 'clumps'; individual plants grow 40 cm to 1.5 m tall. This is the only yellow-flowered iris that grows in water in British Columbia. It has stout rhizomes and long, spreading roots.

Leaves are erect, flattened, and sword-like, mostly basal and are folded and clasp the stem at the base in a fan-like manner.

Flower is large, showy, and yellow. Several flowers can occur on each stem along with one or two leafy bracts. Seeds form in large, glossy green, triangular capsules. The seeds float in water.


Reproduces by seed and rhizome fragments.

Habitat & Ecology

Wetlands, ponds, marshes, slow-moving streams, roadside ditches. Can also grow in salt water.


Mat-forming root mass collects sediment and severely reduces water flow. Can fill in wetlands and streams. Displaces native plants and damages wildlife habitat.


Dig or hand pull small patches for several years to deplete root reserves. Remove entire rhizome mass. As a stop gap measure, clip flowers to prevent seed development and dispersal and remove fruits to prevent them from floating downstream and creating new colonies. All plant parts are toxic so wear gloves and appropriate protective clothing. Take care to ensure that all plant parts have been removed from the area and disposed of by burning or placing in a thick garbage bag and take to the landfill.