Western Blue Flag Iris (Iris missouriensis)

Physical Characteristics

The Western blue flag iris is a handsome beardless iris that grows between 1 and 2 feet tall. The flowers are easily identifiable; large purple blossoms with white or sometimes yellowish veins. Depending on the region, the Western blue flag iris will bloom in the late spring to summer.

Growing Conditions and Distribution

Iris missouriensis is a perennial that grows throughout the Western US and can thrive in a number of different situations; it does well partial shade to shady areas and will also tolerate sun for a portion of the day. The Western blue flag iris can live in moist soils in the spring but is intolerant of water soaked conditions into the summer. Once established, it is drought tolerant. The natural habitats of this iris are meadows, hillsides, and foothills.

The iris borer is a well-documented pest of this species. The iris borer lays its eggs in the plants rhizomes, damaging them, and leading to plant health decline. The best way to avoid the spread of the pest is to remove the infected plant(s) as soon as the borer is identified and destroy them so that other plants will not become infected. The Western blue flag iris makes a wonderful garden specimen and can be easily divided and transplanted.

Conservation Status

Iris missouriensis is considered globally secure; however it is considered imperial in North Dakota and Nebraska and threatened in Alberta, Canada. Like many species, the Western blue flag iris’s habitat is being threatened by land use changes from natural areas to cultivation, grazing, and development.

Pollinator Information

The Iris missouriensis pronounced nectar guides (white and yellow veins on the flower) are an indicator of insect pollination. Irises are generally pollinated by bumble bees, large carpenter bees, and sometimes flies and moths.

Ethnobotany

The Western blue flag iris has been used in many ways. For example, its rhizomes were used superficially to treat infections, wounds and ulcers. However, the rhizomes are toxic if ingested. The fiber was also woven into nets and ropes to catch fish, deer, and other game.

Additional Information

USDA Plants Database - Western Blue Flag Iris (Iris missouriensis)