strict blue-eyed grass

(Sisyrinchium montanum var. montanum)

Conservation Status
IUCN Red List

not listed


NNR - Unranked

SNR - Unranked


not listed

Wetland Indicator Status

FAC - Facultative

Northcentral & Northeast

FAC - Facultative

strict blue-eyed grass
Photo by Dan W. Andree

Strict blue-eyed grass is a common prairie wildflower. It is native to the northern and south-central United States and most of Canada. It was introduced in France, probably during the First World War. It is now naturalized throughout most of Europe. In the U.S., it is found in moist meadows and open woodlands and on stream banks. It grows under full sun in loamy soil. It often forms clumps.

Strict blue-eyed grass is a 4 to 20 (10 to 50 cm) tall, erect, perennial forb that rises on 2 to 6 basal leaves and one or more aerial stems from fibrous roots. It there are underground horizontal stems (rhizomes), they are barely discernible or obscure.

There is some disagreement in the literature about the presence of a waxy film (glaucous) on the stems and leaves. According to Flora of North America, the plant is “not glaucous.” According to Gleason & Cronquist (1992), the plant is “glaucescent”, meaning becoming glaucous. According to Michigan Flora (Voss, 1972) the plant is “with a more glaucous aspect.” According to Minnesota Flora (Chadde, 2019), the plant is “waxy”.

The leaves are mostly from the base of the plant (basal), but one or more may arise low on the stem. The leaf blade is grass-like (linear), narrow, hairless, and 116 to (1.5 to 3.0 mm) wide, almost as long and wide as the stem.

The aerial stem is unbranched, flattened, obviously winged, hairless, and 116 to (2.0 to 3.7 mm) wide. The margins in western populations are toothed near the top, but in eastern populations they are not toothed.

The inflorescence is a single flower or a single, unstalked, flattened, fan-shaped cluster (cyme) of 2 to 11 flowers at the end of the stem. The cyme is subtended by and partially enclosed by a pair of claw-like bracts. Together the bracts are called a spathe, and each bract is called a spathe.

The spathes are hairless, folded (keeled), and usually green or bronze. They rarely have purplish margins. The keel usually has very small teeth. The outer spathe is 1 716 to 3 (36 to 76 mm) long. It is always 916 to 1 1316 (14 to 46 mm) longer than the inner spathe, and it is usually at least (16 mm) longer. It is folded lengthwise and fused at the base for 132 to (1.0 to 3.5 mm), partially enclosing the base in the inner spathe. The inner spathe has very thin, 1256 to 3256 (0.1 to 0.3 mm) wide, membranous, translucent margins from the base to 132 to 532 (0.9 to 4.3 mm) from the tip, which is green. The margin of the outer spathe is distinct all the way to the base.

The flowers are about ¾ (20 mm) in diameter. They are at the end of a slender, hairless, ¾ to 1 (2.0 to 2.5 mm) long stalk. They are drooping when in bud, becoming erect when in flower. Each flower has 3 petals, 3 petal-like sepals (6 tepals), 3 stamens, and 3 styles. The tepals are widely spreading, inversely lance-shaped, and to 916 (9.0 to 14.5 mm) long. They are notched at the rounded tip, and they have a bristle-like extension at the tip. They are usually dark bluish violet, sometimes blue, and they are yellow at the base. The stamens have white filaments and yellow anthers. The filaments are fused for most of their length around the styles. The styles extend between the filaments and beyond the anthers.

The fruit is a tan to dark brown, to ¼ (4 to 6.8 mm) long, globe-shaped to inversely egg-shaped capsule containing many seeds. It is sometimes tinged purple at the tip. It is erect to spreading at the end of a stalk (pedicel).



4 to 20 (10 to 50 cm)


Flower Color

Usually dark bluish violet, rarely blue, and yellow at the base


Similar Species

Prairie blue-eyed grass (Sisyrinchium campestre) flowers are usually pale violet or light blue, sometimes white.


Dry to moderate moisture. Moist meadows, open woodlands, and stream banks. Full sun. Loamy soil.



May to July


Pests and Diseases





Distribution Map



2, 3, 4, 5, 7, 24, 28, 29, 30.









Plantae (green algae and land plants)


Viridiplantae (green plants)


Streptophyta (land plants and green algae)


Embryophyta (land plants)


Tracheophyta (vascular plants)


Spermatophytina (seed plants)


Liliopsida (monocots)


Asparagales (agaves, orchids, irises, and allies)


Iridaceae (irises and allies)






Sisyrinchium (blue-eyed grasses)




Sisyrinchium montanum (strict blue-eyed grass)


There are two recognized varieties of Sisyrinchium montanum: S. m. montanum, common and widespread across the northern United States and southern Canada; and S. m. crebrum, restricted to the northeast. USDA PLANTS and NatureServe show S. m. crebrum as native to Minnesota. However, there are no records of it in the state, and the Minnesota DNR (MNTAXA) does not list it for the state.


Subordinate Taxa




Sisyrhinchium alpestre

Sisyrinchium alpestre

Sisyrinchium heterocarpum


Common Names

American blue-eyed-grass

mountain blue-eyed grass

strict blue-eyed grass











A branched, flat-topped or convex flower cluster in which the terminal flower opens first and the outermost flowers open last.



Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.



Folded, as in a grass blade, or with a raised ridge, as in a grass sheath; like the keel of a boat.



Long, straight, and narrow, with more or less parallel sides, like a blade of grass.



On plants: the stalk of a single flower in a cluster of flowers. On insects: the second segment of the antennae. On Hymenoptera and Araneae: the narrow stalk connecting the thorax to the abdomen: the preferred term is petiole.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.



An outer floral leaf, usually green but sometimes colored, at the base of a flower.



One or two large bracts that subtend, hood, or sometimes envelope a flower or flower cluster, as with a Jack-in-the-Pulpit.



Refers to both the petals and the sepals of a flower when they are similar in appearance and difficult to tell apart. Tepals are common in lilies and tulips.



What’s in a Name?

Contrary to its common name, strict blue-eyed grass is an iris, not a grass.

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Dan W. Andree

Blue-eyed Grass...

Shows somewhat how small the flowers are when it blooms.… It seems to be blooming a lot now and I seen many little purplish flowers, but they all looked so similar and none much different than any other.


strict blue-eyed grass Photos











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Other Videos

Wild Iris Sisyrinchium montanum var montanum
Rocky Mountain Biological Lab Videos


Jun 29, 2020

Mountain Blue-eyed Grass Wildflowers ~ Sisyrinchium montanum
The Snowflake Photographer


Jun 1, 2022

Order prints at under Creative or Nature link or follow me on Facebook "The Snowflake Photographer"



Visitor Sightings

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Dan W. Andree
Spring 2024

Location: SNA in Norman Co. Mn.

Shows somewhat how small the flowers are when it blooms.… It seems to be blooming a lot now and I seen many little purplish flowers, but they all looked so similar and none much different than any other.

strict blue-eyed grass Sightings





Created: 6/30/2024

Last Updated:

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