Where it's from

North Africa and western Asia

What Water chestnut / European water chestnut does to the habitat

Yellow iris forms dense colonies that inhibit native plants out competing them for space and light. It is poisonous to grazing cattle and wildlife as the leaves contain glycosides.

Management

CAUTION: Use gloves when pulling the plant by hand as it may cause skin irritation. Some people use mechanical harvesters or chopping machines.

You can also cut the iris and paint the cuts with Round Up. Yellow Iris is susceptible to many registered herbicides, but is resistant to terbutryne.

DESCRIPTION

Botanical Glossary

Iris pseudacorus is a herbaceous perennial that can grow up to 0.9-1.2 m (3-4 ft.) in height. The broad, sword-shaped leaves are stiff, erect and glaucous. They measure between 0.5-1 m (1.6-3.3 ft.) long and 1-3 cm (0.4-1.2 in.) wide. The rhizomes are pink-fleshed and 1-4 cm (0.4-1.6 in.) in diameter. The showy flowers of Iris pseudacorus bloom from April to June. Most often they are yellow, but their color can also range from nearly white to cream. The flowers are 7-9 cm (2.75-3.5 in.) wide. They are borne on erect peduncles and there are several flowers on each stem. There are six perianth segments that are clawed. Three of these are upward-pointing petals and three are downward spreading sepals. These sepals often have purple, brown or red veins on their yellow surface. The fruits are 4-8 cm (1.6-2.7 in.) long capsules. These capsules are 6-angled and cylindric-prismatic to ellipsoid in shape. The average capsule contains around 120 seeds that start out white, then harden and turn brown as the season goes on. Page References Bailey 273, Crow & Hellquist 323, Fernald 462, Gleason & Cronquist 484, Holmgren 810, Magee & Ahles 357, Newcomb 120, Peterson & McKenny 100, Seymour 191.