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Bransford, W.D. and Dolphia

Iris douglasiana

Iris douglasiana Herb.

Douglas Iris, Mountain Iris, Western Iris

Iridaceae (Iris Family)

Synonym(s): Iris douglasiana var. major, Iris douglasiana var. oregonensis

USDA Symbol: irdo

USDA Native Status: L48 (N)

The rhizomes of Mountain Iris or Douglas Iris spread slowly, eventually creating a 2-4 ft. wide clump. Tufts of 1-2 ft., sword-shaped, dark-evergreen leaves arise from the rhizome and surround a flowering stalk of equal height. Several showy iris blossoms emerge from leafy bracts atop the stalks. The flowers are usually blue, though the colors can range from pale cream to yellow to reddish purple. Large, reddish-purple, pinkish, white, or cream flowers, with lilac veins, on stout branched stalks rising from clumps of sword-shaped leaves.

This is a common iris in the Redwood region. The genus name, Greek for "rainbow," refers to the variegated coloration of the flower. In Greek mythology, Iris, a member of Hera's court and goddess of the rainbow, so impressed Hera with her purity that she was commemorated with a flower that blooms in the rainbow colors of her robe.

From the Image Gallery

3 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Herb
Fruit Type: Capsule
Size Notes: Up to about 2 feet tall.

Bloom Information

Bloom Color: White , Blue , Purple
Bloom Time: Mar , Apr , May , Jun

Distribution

USA: CA , OR
Native Distribution: Coastal region from Santa Barbara Co., CA to Coos Co., OR
Native Habitat: Grassy slopes; open woods

Growing Conditions

Light Requirement: Part Shade
Soil Moisture: Moist
Soil pH: Acidic (pH<6.8)
Soil Description: Moist to dry, nutrient-rich soils.
Conditions Comments: Douglas iris is a vigorous, shade and drought tolerant iris. Crosses with I. innominata and other West Coast species are collectively called Pacific Coast hybrids.

Benefit

Conspicuous Flowers: yes

Propagation

Description: Increase by seed or rhizome divisions. Divide rhizomes in late fall or early spring but cutting the leaves back to about 5 in. and then cutting between the tufted clumps. Plant fresh seeds in early fall in permanent location or flats that are left out o
Seed Collection: Easily collected from the large capsules.
Seed Treatment: No pretreatment is necessary, although a moist stratification (3 mo. at 40 degrees) may be beneficial.
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.

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

Santa Barbara Botanic Garden - Santa Barbara, CA
Native Seed Network - Corvallis, OR

Bibliography

Bibref 995 - Native Landscaping from El Paso to L.A. (2000) Wasowski, S. and A. Wasowski

Search More Titles in Bibliography

Web Reference

Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter

From the Archive

Wildflower Newsletter 1984 VOL. 1, NO.4 - Lady Bird Heartened by Progress, Horticultural Society Annual Meeting Held, Dire...

Additional resources

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

Metadata

Record Modified: 2023-02-14
Research By: TWC Staff

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