Blue-eyed grass (Sisyrinchium angustifolium)
Discover Sisyrinchium angustifolium, a clump-forming perennial known as Blue-eyed grass, thriving in zones 4-9.
Complete Plant Information
Overview
Blue-eyed grass, scientifically known as Sisyrinchium angustifolium, offers delightful, showy flowers that appeal to native plant enthusiasts and general gardeners alike. Despite its common name, this charming plant belongs to the Iris family (Iridaceae), not the grass family, evidenced by its distinct violet-blue blooms set against narrow, grass-like foliage. It forms neat clumps, making it an excellent low-maintenance addition to informal garden settings throughout North America.
Valued for its dependable spring bloom, Sisyrinchium angustifolium is native to damper, open woodlands and slopes. It typically reaches heights around 1.5 to 2 feet, forming tufts of thin leaves that provide fine texture in the landscape. Its ease of naturalization is a major benefit, allowing it to spread gently where conditions are ideal, brightening borders and woodland margins.
Gardeners appreciate the striking contrast between the bright blue flowers, each marked with a tiny yellow eye, and the deep green, blade-like leaves. For those seeking low-risk specimens, blue-eyed grass presents no serious insect or disease concerns, offering reliable seasonal color and texture with moderate cultural needs.
Fast Facts
- Plant Family: Iridaceae
- Plant Type: Herbaceous perennial
- Native Range: North America
- Hardiness Zones: USDA Zones 4-9
- Size at Maturity:
- Height: 1.5-2 ft
- Spread: 0.5-1 ft
- Bloom Time: May to June
- Bloom Description: Blue
- Sun Exposure: Full sun to part shade
- Water Needs: Medium
- Maintenance Level: Medium
How to Grow
Sisyrinchium angustifolium establishes best when planted in the spring or fall in locations receiving full sun to partial shade. The critical soil requirement is that it must be well-drained, even though the plant prefers consistently moist conditions. Avoid heavy, waterlogged clay, as good drainage is essential for preventing bulb rot.
Maintain medium moisture levels throughout the growing season; this plant prefers soils that do not significantly dry out. While it can self-seed freely in perfect conditions, regular care involves ensuring sufficient water during dry spells. Fertilization is rarely needed if adequate organic matter is present in the soil initially.
To manage spread or tidy the appearance, plantings of blue-eyed grass can be sheared back once flowering concludes in late June. Allowing plants to set seed may lead to naturalizing, which is desirable in wild gardens. To maintain vigor, especially in established clumps, plan on dividing Sisyrinchium angustifolium every two to three years.
Landscape Uses
Blue-eyed grass excels when utilized in naturalized settings, perfectly suiting informal garden designs such as cottage gardens, woodland gardens, or native plant areas. Its fine texture and bright blooms work beautifully as a textural element contrasting with broader-leaved perennials. It functions excellently near the front of borders, softening edges where perennial beds meet pathways.
As a ground cover or mass planting, Sisyrinchium angustifolium creates a cohesive, shimmering effect during its bloom period. Consider pairing it with spring ephemerals or later-blooming woodland flowers that appreciate similar moisture levels. Its suitability as an edger for paths or walkways allows the blue flowers to be closely appreciated without overshadowing surrounding hardscaping.
Standout Features
Flower Qualities
- Showy
- Good Cut
Noteworthy Characteristics
Sisyrinchium angustifolium, commonly called blue-eyed grass, is noted for its violet-blue flowers and branched flowering stems. Though its foliage is grass-like, the blue-eyed grasses belong to the iris family not the grass family. It is native to Missouri where it occurs in damp open woods, slopes and along stream banks throughout much of the State.
Tolerances
Potential Problems
Fortunately, blue-eyed grass is generally robust and presents no serious insect or disease problems under appropriate growing conditions. Cultural issues usually stem from excessively poorly drained soil, which can lead to crown and root rot, especially during wet winters. Ensure the planting site adheres to the requirement for well-drained soil to prevent these issues proactively.
Frequently Asked Questions
What hardiness zones is Blue-eyed grass suitable for?
Sisyrinchium angustifolium is reliably hardy across USDA Zones 4 through 9.
How large does Blue-eyed grass grow?
This clumping perennial generally reaches a height between 1.5 and 2 feet tall, with a spread of 0.5 to 1 foot wide.
What sun exposure does Sisyrinchium angustifolium need?
Blue-eyed grass performs best in conditions ranging from full sun to partial shade.
When does Blue-eyed grass bloom?
The bloom time for Sisyrinchium angustifolium is typically from May to June, featuring lovely blue flowers.
Conclusion
The striking blue blooms and fine, grass-like texture establish Sisyrinchium angustifolium as a valuable, easily maintained plant for naturalizing or border detailing. This excellent perennial, Blue-eyed grass, offers minimal fuss once established in moist, well-draining soil. Check your specific microclimate against the USDA Zones 4-9 range and plan to incorporate its spring color into your garden design this year.
Companion Planting
When selecting companions for Sisyrinchium angustifolium, opt for other moisture-loving woodland or native edge plants that do not smother its low-growing habit. Good partners include various native sedges (Carex species) which share similar soil and water needs, providing textural contrast throughout the season. For color contrast during the bloom period, pair the blue flowers with early-blooming yellow perennials like certain varieties of native buttercups or spring starry false Solomon’s seal.
Propagation Tips
Propagation of Sisyrinchium angustifolium is easily achieved through division or natural self-seeding. If you wish to control spreading, divide the clumps every few years in early spring or fall before or after the main flowering period. Simply lift the clump and gently separate the rooted sections, replanting immediately at the same depth. Self-seeding is also prolific in ideal locations; you can allow this natural process or shear back plants after flowering to prevent unwanted dispersal.
