Blue-eyed grass (Sisyrinchium angustifolium 'Lucerne')
Sisyrinchium angustifolium 'Lucerne' offers intense blue, star-like flowers in late spring. This Blue-eyed grass is adaptable and perfect for borders.
Complete Plant Information
Overview
Sisyrinchium angustifolium ‘Lucerne’, commonly known as Blue-eyed grass, brings exceptional color to the garden border during late spring. This compact perennial is prized for its dense tufts of narrow, grass-like foliage, which provides excellent texture even when not in bloom. It is a reliable choice for adding consistent, vibrant blue tones to mixed plantings.
Despite its common name, Blue-eyed grass is a member of the Iris family (Iridaceae), not the true grasses. The cultivar ‘Lucerne’ stands out due to its larger, intense blue, star-like flowers, which reach up to one inch in diameter and feature distinct yellow centers. A key benefit of Sisyrinchium angustifolium ‘Lucerne’ is its relatively tidy nature compared to the species, as it reportedly does not self-seed as aggressively.
This clump-forming plant thrives in average, consistently moist garden settings under full sun or partial shade. Its small stature makes the Blue-eyed grass highly versatile for edging pathways or filling in rock gardens, offering a punch of color reliably between May and June.
Fast Facts
- Plant Family: Iridaceae
- Plant Type: Herbaceous perennial
- Hardiness Zones: USDA Zones 4-8
- Size at Maturity:
- Height: 0.5-1 ft
- Spread: 0.5-0.75 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
Plant Sisyrinchium angustifolium ‘Lucerne’ in spring or fall in a location offering full sun to light afternoon shade. The soil must be well-drained, although the plant prefers consistently medium moisture and dislikes drying out completely. Good drainage is essential to prevent crown rot, even though the Blue-eyed grass appreciates damp conditions.
Water medium moisture needs by ensuring supplemental water during extended dry spells, especially when establishing. Fertilization is rarely necessary if the soil quality is adequate; excessive richness can lead to floppy foliage rather than prolific blooming. No specific fertilizer regime is typically required for this robust perennial.
After the main bloom period concludes in June, you may shear the foliage back to neaten the appearance or prevent any minor self-seeding. Although ‘Lucerne’ is less prone to seeding than wild types, this tidies the patch for the rest of the season. Plants benefit from division every two to three years to maintain vigor and prevent overcrowding within the clump.
Landscape Uses
Sisyrinchium angustifolium ‘Lucerne’ excels in informal and naturalized garden settings where its fine texture can contrast with coarser companions. It is highly effective when incorporated into woodland gardens, native plant areas, or cottage borders, mimicking its preferred native habitat along stream banks. The vibrant blue flowers draw the eye, making it an excellent choice for the fronts of borders.
Utilize Blue-eyed grass as a low, neat edger along flagstone paths or walkways where its mounding habit prevents encroachment. Because it stays relatively contained, it also works well in rock gardens, tucked between stones or anchoring low drifts. Consider pairing Sisyrinchium angustifolium ‘Lucerne’ with plants that share similar moisture requirements but offer contrasting foliage, such as ferns or sedges.
Standout Features
Flower Qualities
- Showy
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. 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.Genus name comes from the ancient Greek name for another plant.Specific epithet means narrow-leaved.‘Lucerne’ was discovered growing in a nursery near Lucerne, Switzerland. It is noted for its profuse bloom of large, one inch diameter, star-like, intense blue flowers with yellow centers over a long May-June bloom period
Tolerances
Potential Problems
This plant is highly valued for its minimal pest and disease issues, generally exhibiting no serious insect or disease problems. Proper cultural care, particularly ensuring that the soil drains well despite the need for medium moisture, is the best preventative measure. Avoid excessive alkalinity or extremely dry soil conditions to keep your Sisyrinchium angustifolium ‘Lucerne’ healthy.
Frequently Asked Questions
What hardiness zones is Blue-eyed grass suitable for?
Sisyrinchium angustifolium ‘Lucerne’ is suitable for USDA Zones 4 through 8.
How large does Blue-eyed grass grow?
This perennial typically reaches a height between 0.5 and 1 foot, with a spread of 0.5 to 0.75 feet wide.
What sun exposure does Sisyrinchium angustifolium ‘Lucerne’ need?
It performs best when sited in locations receiving full sun to partial shade.
When does Blue-eyed grass bloom?
The bloom time for this cultivar is generally from May to June, featuring distinctively blue flowers.
Conclusion
The Sisyrinchium angustifolium ‘Lucerne’ offers unparalleled value as a low-maintenance perennial that delivers intense color in late spring. Its grass-like texture and vibrant blue flowers make this Blue-eyed grass a foundational element for structured yet natural garden designs. Before planting, confirm your garden site falls within USDA Zones 4-8 and verify that your soil offers adequate drainage.
Companion Planting
For optimal growth, pair Sisyrinchium angustifolium ‘Lucerne’ with plants that share requirements for medium moisture and sun exposure but provide textural contrast. Consider planting alongside low-growing ferns, which appreciate similar damp environments and offer delicate, contrasting green foliage. Shasta Daisies or low-growing native geraniums also blend well, as they too benefit from consistent moisture throughout the blooming season.
Propagation Tips
While the species form of Blue-eyed grass can be prodigious self-seeders, the ‘Lucerne’ cultivar is usually managed through division for propagation success. To rejuvenate older clumps, divide the established masses every 2 to 3 years, ideally in early spring before new growth accelerates or in early fall. Ensure each division retains several healthy tufts of the narrow, grass-like leaves attached to viable root sections for successful re-establishment in the garden.
