Blue Eyed Grass or Sisyrinchium angustifolium Mill. [sis-ee-RINK-ee-um, an-gus-tee-FOH-lee-um] is noted for its ornamental violet-blue flowers and narrow-leaf foliage.
It is an herbaceous perennial from the iris family, Iridaceae and subfamily Iridoideae.
Others in the family include:
- Louisiana Iris
- Peacock Orchid
It is also known as Sisyrinchium graminoides.
The Sisyrinchium angustifolium plant is native to meadow and woodland climates in the eastern United States.
Its range isn’t limited to the US and extends further into North America and Eastern Canada.
There, it grows in temperate meadows, low open woods, and along shorelines.
The botanical name refers to the narrow leaves of the foliage.
The common names include:
- Narrow-leaf blue-eyed grass
- Common blue-eyed grass
- Stout blue-eyed grass
- Grass flower
Sisyrinchium Angustifolium Care
Size & Growth
In the right growing conditions and a little bit of care, these herbaceous plants can grow up to 12” inches tall.
Blue-eyed grass, despite being grass-like isn’t from the grass family but the iris family.
It is a clump-forming plant, producing grassy leaves 3/16” inches wide.
In some varieties, the leaves may grow as tall as 20” inches.
The tidy foliage is decorated with an abundance of tiny purple flowers with yellow centers at bloom time.
Flowering and Fragrance
They make excellent cut flowers and perfect for wildflower gardens. The blooms on S. angustifolium grow on branched flowering stems.
These violet-blue flowers have pointy tepals and a yellow eye in the center.
The flowers bloom atop branched stems in the spring season (early spring to late spring).
The stems grow from stalks forming leaf-like bracts.
The Sisyrinchium angustifolium ‘lucerne’ variety, found in Lucerne, Switzerland, produces larger blooms in more quantity.
It usually has a longer bloom time than S. angustifolium.
Light & Temperature
These plants are hardy to USDA Hardiness Zones 4 through 9, succeeding in moist meadows, woodlands, pinelands, fields, marshes, grassy roadsides, and even in swamps.
The plants prefer full sun but can tolerate part shade.
Watering and Feeding
Moist soils with good drainage are the way to go with blue-eyed grass.
Space watering cycles so the soil doesn’t dry out in between.
If early summers get too hot, water plants more often.
Avoid overwatering and drowning the rhizomes.
Fertilizing is not necessary.
Soil & Transplanting
All these plants need is a moist, well-drained soil with substantial nutrients to succeed.
Transplanting should be done every 2 to 3 years when dividing plants for increased growth in other naturalized areas.
Grooming and Maintenance
Sisyrinchium plants are low maintenance requiring little to keep these plants going strong.
Since the flowers ‘clean’ themselves and are unobtrusive, deadheading plants is not needed.
How To Propagate Stout Blue-eyed Grass
Propagation is most successfully done by diving the rhizomes, tubers, corms or bulbs.
Or remove offsets produced after the growing season.
Remove the division or cutting to a new location and bury them at the same height as before in well-drained soil.
Water the soil to moisten it and add organic compost if the soil is poor.
If you’re starting from seeds, allow the seed capsules to dry on the plant and break open to collect them.
Mix the seeds with sand and scatter on top of the soil, lightly compressing them.
Don’t bury them or they might have trouble germinating.
Water the plants regularly until they reach 4”-6” inches in height and them more them to permanent locations, spacing them 9”-12” inches apart.
Stout Blue-Eyed Grass Pest or Diseases
These plants are low-maintenance.
They are not susceptible to any serious disease or insect problems.
But do check for aphids and other problems common with other evergreens and iris plants.
Sisyrinchium Angustifolium Uses
Being grass-like, these plants are best displayed when used as a groundcover or when naturalized to garden areas.
The flowers will put on a great show when planted in cottage gardens, woodland gardens, and wildflower gardens.
They also look great as edging and along borders in rock garden, pathways or walkways.
Another species, Sisyrinchium bermudiana produces similar flowers to S. angustifolium.
These flowers are used as a totemic flower by the Bermudians.
The flowers are also effective in attracting pollinators, benefiting other plants around them.