Rocky Mountain Iris
Iris missouriensis Nutt.
Family: Iridaceae, Iris
Genus: Iris
Other names: Western blue flag
Nomenclature: missouriensis = of Missouri
Nativity / Invasiveness: Montana native plant
Edible plant
Medicinal plant
Poisonous plant

General: perennial, widely spreading from thick rhizomes. Flowering stems clumped, shorter to slightly longer than the leaves, 20-50 cm tall, simple, leafless except at the base, often with bluish, waxy coating.

Leaves: mainly basal, linear, sword-shaped, 20-40 cm long, mostly 5-10 mm broad. The involucral (spathe) leaves at the flower base are contiguous, rather inflated, often membranous.

Flowers: usually 2, sometimes 3 or 4, showy, rather pale blue, the individual stalks stout and up to 6 cm long. The 3 sepals oblanceolate, backward-curved, mostly 5-6 cm long, whitish to light blue, strongly purple-lined, joined at the base to a perianth tube 5-8 mm long. The 3 petals light blue with paler lining, erect, slightly shorter than the sepals. The 3 style branches 20-25 mm long, the crests scarcely half as long. May-early July.

Fruits: capsules, 3-5 cm long, with 3 compartments containing dark brown seeds.


Meadows and streambanks, often where apparently very dry, but always where moisture is abundant until flowering time, in w. and c. parts of MT. Also from B.C. to s. CA, e. of the Cascades in WA, e. to SD, ND and s. to n. Mexico.
Edible Uses

The roasted seeds of Rocky Mountain iris can be used as a coffee substitute.

Medicinal Uses

Rocky Mountain iris was employed medicinally by several native North American Indian tribes who used it to treat various complaints, but especially as an external application for skin problems. It was for a time an officinal American medicinal plant, but is little, if at all, used in modern herbalism. The root has agents that induce vomiting, and that treat toothache temporarily, and other problems of the teeth and gums. An infusion has been used in the treatment of kidney and bladder complaints, stomach aches etc. The pulped root is placed in the tooth cavity or on the gum in order to bring relief from toothache. A decoction of the root has been used as ear drops to treat earaches. A poultice of the mashed roots has been applied to rheumatic joints and also used as a salve on venereal sores. Caution is advised in the use of this plant, see the notes above on toxicity. A paste of the ripe seeds has been used as a dressing on burns.

Poisonous Properties

The roots are poisonous. An arrow poison was made from the ground-up roots. Plants can cause skin irritations and allergies in some people.

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