Invasive Plant

Yellow Flag Iris

Iris pseudacorus

Warning

Can be toxic to humans and animals and cause human skin irritations.

About This Species

Yellow flag iris invades ditches, wetlands, streams, lake shorelines, and shallow ponds. This plant reproduces through seed dispersal, horizontal roots, and when pieces of the roots break off, which can form new plants. The seeds float on the water in spring and fall, causing them to spread quickly. 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 to Identify

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

REPORT TO PROTECT BC’S BIODIVERSITY

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INVASIVE SPECIES INFORMATION

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Take Action

Prevention is the best approach.

Yellow flag iris Factsheet
If you need advice about invasive species on your property or you are concerned about reported invasives in your local area, contact your local government or regional invasive species organization.

Clean, Drain, Dry

Learn about best practices

The Clean Drain Dry program empowers you to help reduce the spread of invasive plants and organisms to BC waters by following the clean, drain, dry procedure on all watercraft and equipment.

Learn more