Yellow Flag Iris

Iris pseudacorus

Common name:

Yellow Flag Iris

Scientific name:

Iris pseudacorus

Alternative common names:

Yellow flag, yellow iris (English); geel iris (Afrikaans).

Yellow flag iris forms dense growth along riverbanks and the fringes of ponds, competing with indigenous species and altering water flow. It is a perennial moisture-loving plant with yellow flowers and long, strap-like leaves. It reaches a height of 100-150cm.

Additional Info

  • Where does this species come from?

    Europe, western Asia and parts of North Africa.

    What is its invasive status in South Africa?

    NEMBA Category 1a.

    Where in South Africa is it a problem?

    Mostly recorded from Gauteng Province and common around some wetlands in Johannesburg and Pretoria.

    How does it spread?

    Rhizomes spread the plant, as well as seed dispersal. Seeds are spread along by flowing water.

    Why is it a problem?

    This partially aquatic plant forms dense growth along riverbanks and ponds, competing with indigenous plants and altering the flow regime of rivers. This plant also has toxic properties and poisonous to livestock.

    What does it look like?

    Leaves:Long, strap-like leaves, green to bluish-green and erect, with the upper part bending over. Leaves 1m long and 30mm wide. Flowers: Large yellow flowers with three narrow and three broad lobes 70mm long and 40mm wide. Fruit/seeds: Glossy green three-angled capsules which are 40-80mm long.

    Does the plant have any uses?

    Planted as a pond ornamental.