Iris pseudacorus - Yellow Flag Iris - (Iridaceae)

This tall marginal plant is very common beside rivers, lakes and canals throughout Europe. It blooms from May until August, and is one of our best-known and loved wildflowers.

A dense stand of Yellow Flag Irises

The plants form dense stands and spread very easily once established.

A closeup picture of the Iris psuedacorus flower

The stems are often branched, and plants form dense colonies providing sanctuary areas for small fishes such as minnows and sticklebacks and other aquatic wildlife.

Tall iris plants

The Yellow Flag Iris can grow up to a metre in height.

Iris psuedacorus is popular in gardens and is frequently planted around ponds and water features. Some of the plants to be found in the wild have escaped from nearby gardens and, once established in suitable habitat, quickly spread to form large colonies of naturalised plants which are indistinguishable from their wild ancestors.

We have found and photographed this plant in many places in Europe, including the Triglav National Park in Slovenia.

The plants on this page were photographed in Wales in June.