Data provided by the participants of the Consortium of California Herbaria

View additional distribution information on the Jepson eflora

Iris missouriensis (syn. I. montana) is a hardy flowering rhizomatous species of the genus Iris, in the family Iridaceae. Its common names include western blue flag, Rocky Mountain iris, and Missouri flag. It is native to western North America. Its distribution is varied; it grows at high elevations in mountains and alpine meadows and all the way down to sea level in coastal hills. Its leaves are quite unpalatable to wildlife and livestock and the roots are poisonous to humans.



Plant type

Perennial herb, Geophyte

Size

1 - 2 ft Tall

Form

Upright, Spreading

Growth rate

Fast

Dormancy

Winter Deciduous

Calscape icon
Color

Purple

Flowering season

Spring

Special uses

Water features or wet habitats, Deer resistant

Sun

Partial Shade, Full Sun

Water

Low, Moderate, High

Summer irrigation

Max 1x / month once established

Cold tolerance

Tolerates cold to -15° F

Soil drainage

Fast, Medium, Slow

Soil description

Tolerant of a variety of garden soils as long as sufficient moisture is available.
Soil PH: 6.0 - 8.0

Maintenance

Old leaves should be removed.

Propagation

You can separate bulbs, bulb offsets, corms and rhizomes. Frequent divisions tends to keep the plants vigorous. These should be planted immediately, ideally in early Autumn. Seeds can be collected and should be stored at room temperature until planted.

Sunset Zones

1, 2*, 3*, 4*, 5*, 6*, 7*, 9*, 10, 11, 14, 15*, 16, 18*, 19, 20, 21

Site type

Moist, grassy places, such as meadows and streambanks.

Plant communities

Red Fir Forest, Yellow Pine Forest, Wetland-Riparian

Consider pairing with deer fern (Blechnum spicant) or creek dogwood (Cornus sericea), both which also do well in wetter sites.

Caterpillars
Butterflies

Butterflies and moths supported

0 confirmed and 4 likely

Confirmed Likely

American Ear Moth

Amphipoea americana

Verbena Bud Moth

Endothenia hebesana

American Crescent Borer

Helotropha reniformis