Yellow Flag Iris

Iris pseudacorus

MARY

Description

An aquatic perennial that grows 3 to 4 feet tall and forms dense, monotypic stands. The leaves are long, flattened, and sword-like. The showy all-yellow flowers are produced on erect plant stalks with multiple flowers per stalk. When not in bloom, it may be confused with cattail (Typha latifolia) or broad-fruited bur-reed (Sparganium eurycarpum). Look for the fruits in the summer, or the fan-shaped plant-base during the other seasons, and the all-yellow flower. It is the only flower in the Iridaceae family that is completely yellow.

Habitat

Temperate wetlands

Distribution

Willamette Valley, Oregon coast, Columbia River, central Oregon, and northeast Oregon; west of Washington Cascades and northeast Washington; scattered populations in western and southern Idaho

Impacts

Displaces native plants including sedges and rushes, thus reducing the carrying-capacity of wetlands for waterfowl and disrupting other ecological relationships. Also restricts flow in waterways including irrigation canals and flood control ditches.

Dispersal Methods

Water

Prevention

Look for yellow flag iris along riparian areas (e.g. lakes and slow-moving rivers), open water features, and irrigation ditches.

Listings

ODA's B List

Factsheets

Washington State Noxious Weed Control Board Fact Sheet

Photos

http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Iris+pseudacorus

Distribution Map

Distribution in Oregon
Distribution in Washington
Distribution in Idaho

CWMA Warnings

Columbia Gorge

North Coast

Mid-Coast

WEEDIN