Western Iris

A white and purple flower at the top of a green stem is approached by a flying bee against a blurred green background
A bee approaches a Western Iris

NPS Photo/Tiffany Zadi


Western Iris

Iris missouriensis

Common Names: Rocky Mountain Iris, Western Blue-Flag, Missouri Iris
Family: Iridaceae
Flowering Season (Bryce Region): May - July
Size: 12-24" (30-62 cm)
Range: Great Plains to Colorado Plateau

General Description

Its leaves are grasslike and extend to about the height of the flowers. The flowers are about 4 in. across with 3 widely oblanceolate petals. The perianth can be pale lilac to white and veined lilac-purple. It's distinguished by the blue-purple flower. The sepals are blue or purple and drooping, while the 3 blue-purple petals are broad and erect. Three blue-purple narrow pistils arch over the stamens as well.


This flower prefers moist soils and are generally found growing in large colonies in typical wetland habitats. Loss of habitat threatens many of our native irises as they occur in fragile, easily damaged habitats.

Plant Lore

There are approximately 300 species of Iris in the world. According to Greek mythology, Iris was the messenger of the gods, a connection between heaven and mortal human beings here on earth. Iris was the goddess of the rainbow and beautiful flowers sprouted wherever she stepped. This plant is toxic, particularly the rootstalks. However, the Northern Paiute tribe commonly used parts of this plant as a toothache remedy.

Although the specific name missouriensis means "from Missouri", the plant is not found in the state of Missouri. Rather, it was likely named by Lewis and Clark after the region of the upper reaches of the Missouri River of the Rocky Mountains for which it was first discovered.

Further Reading

Buchanan, Hayle 1992. Wildflowers of Southwestern Utah. Bryce Canyon Natural History Association. Bryce Canyon, Utah.

Last updated: July 23, 2023

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