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Native Plant Database

Search for native plants by scientific name, common name or family. If you are not sure what you are looking for, try the Combination Search or our Recommended Species lists.

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Iris missouriensis (Rocky mountain iris)
Bransford, W.D. and Dolphia

Iris missouriensis Nutt.

Rocky Mountain iris, Western blue flag

Iridaceae (Iris Family)

Synonyms: Iris longipetala

USDA Symbol: irmi

USDA Native Status: Native to U.S.

Rocky Mountain iris is slender-stemmed and 1-2 ft. high. One to four flowers occur per stem. They are pale to dark, lilac-purple and haves yellow bases. The grayish-green leaves are relatively broad. Large, delicate, pale blue or blue-violet flowers, often with purple veins, bloom at the top of stout, leafless (or with 1 short leaf) stalks that grow from dense clumps of flexible, tough, sword-shaped leaves.

The only native species east of the Cascade Mountains and the Sierra Nevada, it often forms dense, large patches in low spots in pastures, where the tough leaves are avoided by cattle.

 

From the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Herb
Leaf: Green
Fruit:
Size Class: 1-3 ft.

Bloom Information

Bloom Color: Purple
Bloom Time: May , Jun

Distribution

USA: AZ , CA , CO , ID , MN , MT , ND , NE , NM , NV , OR , SD , UT , WA , WY
Canada: AB , BC
Native Distribution: B.C. to s. CA (mostly e. of the Cascades), e. to the Dakotas, NM & Mex.
Native Habitat: Marshes; wet meadows; drier areas if moist until flowering time
USDA Native Status: L48(N), CAN(N)

Growing Conditions

Water Use: High
Light Requirement: Sun
Soil Moisture: Wet
CaCO3 Tolerance: High
Soil Description: Wet soils.
Conditions Comments: This iris spreads to form colonies. It needs to be divided regularly.

Benefit

Use Wildlife: Hummingbirds
Warning: POISONOUS PARTS: Rhizomes (thickened roots) and rootstocks, fresh or dry. Minor skin irritation when touched, low toxicity if ingested. Symptoms include nausea, vomiting, abdominal pain, diarrhea, elevated temperature following ingestion; skin irritation upon contact with seeds, rootstock, or cell sap. Toxic Principle: Irisin, iridin, or irisine. (Poisonous Plants of N.C.)


Conspicuous Flowers: yes
Attracts: Hummingbirds

Propagation

Seed Collection: Easily collected from the large capsules.
Seed Treatment: Not Available
Commercially Avail: yes

Find Seed or Plants

Find seed sources for this species at the Native Seed Network.

View propagation protocol from Native Plants Network.

Mr. Smarty Plants says

Native shade plants around fountain in California
March 18, 2009
Hi, we just put a fountain in our front yard. It is in a mostly shady area. I need to know what plants would go best around the fountain and survive in the shade.
view the full question and answer

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is either on display or available from the following:

Santa Barbara Botanic Garden - Santa Barbara, CA
Tohono Chul Park, Inc. - Tucson, AZ
Native Seed Network - Corvallis, OR

Bibliography

Bibref 946 - Gardening with Prairie Plants: How to Create Beautiful Native Landscapes (2002) Wasowski, Sally
Bibref 841 - Native Alternatives to Invasive Plants (2006) Burrell, C. C.

Search More Titles in Bibliography

Recommended Species Lists

Find native plant species by state. Each list contains commercially available species suitable for gardens and planned landscapes. Once you have selected a collection, you can browse the collection or search within it using the combination search.

View Recommended Species page

Additional resources

USDA: Find Iris missouriensis in USDA Plants
FNA: Find Iris missouriensis in the Flora of North America (if available)
Google: Search Google for Iris missouriensis

Metadata

Record Modified: 2009-02-20
Research By: TWC Staff

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