Several species in the eastern United States are threatened or endangered.
http://en.wikipedia.org/wiki/Sisyrinchium
http://commons.wikimedia.org/wiki/Category:Sisyrinchium

Common Name: blue-eyed grass
Type: Herbaceous perennial
Family: Iridaceae
Native Range: Southeastern United States
Zone: 4 to 9
Height: 1.50 to 2.00 feet
Spread: 0.50 to 1.00 feet
Bloom Time: May to June
Bloom Description: Blue
Sun: Full sun
Water: Medium
Maintenance: Medium
Suggested Use: Ground Cover, Naturalize
Flower: Showy, Good Cut
Garden locations
Culture

Best grown in medium moisture, well-drained soil in full sun. Tolerates light shade. Prefers consistently moist soils that do not dry out, but drainage must be good. Will freely self-seed in optimum growing conditions. Plantings may be sheared back after bloom to avoid any unwanted self-seeding and/or to tidy foliage for remaining part of the growing season. Plants may need to be divided every 2-3 years to keep plantings vigorous.

Noteworthy Characteristics

Though their foliage is grass-like, the blue-eyed grasses belong to the iris family not the grass family. Sisyrinchium angustifolium is noted for its violet-blue flowers and branched flowering stems. It is native to Missouri where it occurs in damp open woods, slopes and along stream banks throughout much of the State. It is a clump-forming perennial that features a tuft of narrow grass-like leaves (to 3/16″ wide) typically growing to 12″ (less frequently to 20″) tall. Clusters of violet-blue flowers (to 1/2″ across), each with 6 pointed tepals and a yellow eye, appear in spring on stalks growing from leaf-like bracts atop usually branched flowering stems which are distinctively flattened. Sisyrinchium campestre, also a Missouri native, features pale blue to white flowers atop unbranched flowering stems. S. angustifolium includes plants formerly classified as S. bermudianum.

Problems

No serious insect or disease problems.

Garden Uses

Best naturalized in informal garden areas such as cottage gardens, woodland gardens, wild gardens or native plant areas. Also effective in border fronts and rock gardens. Also effective as an edger for paths or walkways.
http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=i870

Blue-Eyed Grass can be a shy, retiring plant at times. They are small perennials, only 10-30 cm (4-12″) tall, with leaves to 3 mm (1/8″) wide. They start opening their eyes in early June and continue to look around all through June. But you have to be a morning person. Sometimes I have gone to photograph those pretty blue eyes in the afternoon only to find that they have already closed their eyes for the day. And just try to find them when their eyes are closed! Their medium green grass-like leaves fade into the background and mingle shyly with all the prairie grasses around them.

Each pretty blue eye sheds a tear when it is finished blooming, in the form of a small round seed capsule filled with tiny black seeds. Perhaps they are tears of happiness or perhaps they are tears of sorrow. We can only speculate. This plant is also known as Star Grass by some people because the flowers are distinctly star shaped. Blue-Eyed Grass is actually not a true grass, but a member of the Iris family, closely related to Blue Flag or Wild Iris (Iris versicolor).

Native Habitat

Blue-Eyed Grass is a native perennial that grows across the prairies and parklands in open meadows. I have seen it growing in a field in northwest Winnipeg along with Prairie Crocus and Three Flowered Avens. John Morgan (Prairie Habitats – see Gardening with Native Prairie Plants) also reported seeing a hillside covered with blooming plants in the Carberry Hills of Manitoba.
http://www.naturenorth.com/spring/flora/begrass/Fbegrass.html

Narrowleaf blue-eyed grass, Narrow-leaf blue-eyed-grass, Bermuda blue-eyed grass, Blue-eyed grass
Iridaceae (Iris Family)

Synonym(s): Sisyrinchium bermudiana, Sisyrinchium graminoides
USDA Symbol: SIAN3
USDA Native Status: L48 (N), CAN (N)

The numerous, narrow, light-green leaves of this perennial form dense, tufted clumps which steadily grow with new foliage during the season. The flattened, leaf-like flowering stems may be up to 18 in. long and bear light-blue, star-shaped flowers a few inches above the leaves. Height is 1-1 1/2 ft. Several delicate, blue or deep blue-violet flowers with yellow centers in 2 broad bracts top a flat stem, generally only 1 flower at a time in bloom; stems taller than the clusters of narrow, sword-shaped leaves near base.

Although the plant is small and has grass-like leaves, the flowers have all the features of the Iris family. The various species are all much alike and separation is based on such characteristics as branching pattern and leaf length. Common Blue-eyed Grass (S. montanum) is also a widespread species, with slightly wider leaves, over 1/4 (6 mm), and unbranched stalks.

PLANT CHARACTERISTICS
Duration: Perennial
Habit: Herb
Size Notes: 1-1.5 feet.
Leaf: Green
Fruit: Brown
Size Class: 1-3 ft.

BLOOM INFORMATION
Bloom Color: Blue
Bloom Time: Mar , Apr , May , Jun , Jul

Native Habitat: Meadows; damp fields; low, open woods

GROWING CONDITIONS
Water Use: Medium
Light Requirement: Sun , Part Shade
Soil Moisture: Moist , Wet
CaCO3 Tolerance: Low
Soil Description: Moist, poor to average soils
Conditions Comments: This short-lived perennial will decline if allowed to dry out. Heavy mulch causes crown rot and rich, organic soils encourage rank, vegetative growth. Plants need to be divided at least every other year.

BENEFIT
Use Medicinal: Amerindians used root tea for diarrhea (in children); plant tea for worms, stomachaches. Several species used as laxatives. (Foster & Duke)
Conspicuous Flowers: yes
Deer Resistant: No

PROPAGATION
Propagation Material: Seeds
Description: Propagate by seed or division. Several dozen divisions can be expected from a mature, healthy specimen.
Seed Collection: Collect seed capsule when they have darkened to brown and become wrinkled.
Commercially Avail: yes

FIND SEED OR PLANTS
Find seed sources for this species at the Native Seed Network.
http://www.wildflower.org/plants/result.php?id_plant=SIAN3