[The Iris Family East of the Cascade Mountains of Oregon and Washington]

Rocky Mountain Iris, Western Blue Flag, Western Iris

Iris missouriensis

Close-up of the flower of Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

The photo above shows a close-up of the inflorescence of western blue flag as seen several miles northeast of Glenwood, WA........June 2006.

Seed pod of Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensisThe photo at right shows the dried seed pod (from the 2005 season) and several seeds of western blue flag.
Characteristics:

Western blue flag is a pretty wildflower which spreads easily via thick rhizomes to form broad clusters, which often appear ring-like as the older plants in the middle die. The stems arise 30-90 cm with 2-4 thick grass-like leaves 20-40 cm long and 5-10 mm wide.

The 1-4 light blue to violet-blue flowers measure about 7.5 cm across. The 3 petals often stand upright and they tend to be slightly shorter than the 3 spreading sepals which are oblanceolate in shape and 5-6 cm long. The throat may have a splash of yellow, and the petals and sepals may have blue penciled lines (as seen in the photos).


Habitat:

Western Blue Flag is common in meadows which remain moist until the time of flowering. It is most common in valley bottoms, but may be found in moist areas amongst sagebrush or beneath Ponderosa Pines.


Range:

Western blue flag is widespread east of the Cascade Mts, east to the Dakotas, north to British Columbia and south to northern Mexico.


Use:

Western blue flag is a pretty native iris for gardens east of the Cascades! In addition, the rootstalks contain a toxin known as irisin, which can be lethal if eaten.


Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis - Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

Western blue flag blooming along Crook County Road 123 about a mile east of the US Highway 26 junction, Crook County, OR.......May 19, 2018.

Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis - Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

Western blue flag in bloom along the Umtanum Falls Trail, Yakima County, WA......May 25, 2019.

Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

Western blue flag blooming along the Line Butte Trail #807 on the south side of Lookout Mt., Ochoco National Forest.........June 22, 2017.

Flower of Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis


Flower of Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis - Flower of Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

The photo at left shows a close-up of the flower of western blue flag as seen along the Indian Painted Rocks Trail along the lower Spokane River.........June 2, 2008. The photo at right shows a close-up view of the flower of western blue flag as seen along Indian Creek, northwestern corner of Big Summit Prairie, Ochoco National Forest........June 3, 2018.

Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis - Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis - Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

Western blue flags still in bloom in wetlands along the North Fork Crooked River about one and one-quarter mile south of the junction of FS Road #42 and #4215, Ochoco National Forest..........June 12, 2015.

ocky Mountain Iris, Rocky Mt. Iris, Western Blue Flag: Iris missouriensis - Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis

Western blue flag blooming (left) with clustered field sedge (Carex praegracilis) at its feet in meadows near Rock Creek, Escure Ranch (BLM), eastern Adams County, WA.........May 14, 2011. The photo at right shows western blue flag in bloom in wetlands surrounding alkaline flats at Hot Springs Campground, Hart Mt. National Antelope Refuge........June 9, 2016..

Flower of Rocky Mountain Iris, Western Blue Flag, Western Iris: Iris missouriensis


Paul Slichter