Articles

Rain Garden Plants: Blue-Eyed Grass

An informative guide with details and pictures of Blue-eyed Grass (Sisyrinchium angustifolium).
Updated:
June 24, 2026

Blue-eyed grass is not a grass; it is a perennial in the iris family. It has star-shaped, ¾-inch blue flowers with yellow centers. The dainty flowers close in the afternoon or evening and open in the morning. Branching stems are longer than leaves. It has grass-like, semi-evergreen leaves that form dense clumps. Blue-eyed grass spreads via rhizomes or self-seeds, and seed capsules are filled with tiny, black seeds. It is drought tolerant and deer resistant.

  • Height: 4 to12 inches
  • Bloom color: Blue
  • Bloom time: May to June
  • Hardiness zone: 5 to 9
  • Salt tolerance: N/A
  • Spreading habit: Self-seeds, clump-forming
Clumps of blue-eyed grass in flower
Blue-eyed grass growing in clumps. Photo credit: Jodi Sulpizio, Penn State Extension

Site Conditions

  • Sun: Sun/partial shade
  • Soil: Consistently moist, well-drained
  • Hydrologic zones: Dry
Overhead view of blue-eyed grass
Overhead view of Blue-eyed grass. Photo credit: Jodi Sulpizio, Penn State Extension
Closeup view of a dried up seed head
Close-up of seed capsule. Photo credit: Jodi Sulpizio, Penn State Extension
Star-shaped blue flower with yellow center.
Flower. Photo credit: Jodi Sulpizio, Penn State Extension

Sources

Missouri Botanical Garden.

Prepared by Jessica Chou, Jodi Sulpizio, and Constance Schmotzer.

For a printable PDF version of this article, contact Jodi Sulpizio at jrb143@psu.edu.Â