How to Grow Blue Eyed Grass
Sisyrinchium bellum
Blue eyed grass is a charming, small iris-family perennial that produces star-shaped blue-violet flowers with yellow centres from spring to early summer. Plant in full sun in well-drained soil — it thrives in poor, even gravelly conditions and is drought-tolerant once settled. Deadhead spent flowers to extend the season and reduce self-seeding. Divide congested clumps every two to three years to keep plants vigorous. Though individual plants are short-lived, colonies persist indefinitely through self-seeding.
Yearly Lifecycle
Care Essentials
Feed sparingly with a balanced fertilizer in early spring as new growth emerges. Avoid high-nitrogen feeds — rich soil causes lush foliage at the expense of flowers. A light top-dressing of compost in spring is usually sufficient.
Watch For
- Slugs and snails on young growth in damp conditions
- Crown rot in heavy, waterlogged soil
- Spider mites in hot, dry weather
Companions
Erigeron (fleabane), Armeria (thrift), Festuca glauca (blue fescue), Dianthus (pinks), Sedum
Track your Blue Eyed Grass care schedule — pruning, feeding, and seasonal tasks
Start planning freeCare Requirements
☀️ Light
Full sun to light shade
Blue eyed grass thrives in full sun and flowers most freely in a bright, open position. It tolerates light shade but produces fewer flowers. A south- or west-facing border or gravel garden is ideal. Avoid deep shade.
💧 Watering
Moderate; drought-tolerant once established
Water regularly in the first season after planting to help establishment. Once settled, blue eyed grass is drought-tolerant and rarely needs watering except during prolonged dry spells. Good drainage is more important than watering frequency — soggy soil is fatal.
🌱 Fertilizing
Little or none needed
Blue eyed grass thrives in poor to moderately fertile soil. A light top-dressing of compost or a balanced slow-release fertilizer in early spring is all that is needed. Avoid high-nitrogen feeds, which produce lush leaves but poor flowering.
✂️ Pruning
Deadhead regularly; tidy in autumn
Remove spent flowers throughout the flowering season to prolong blooming and limit self-seeding. Cut back untidy or yellowing foliage to the base in late autumn. Divide congested clumps every two to three years to maintain vigour.
🍂 Mulching
Light mulch to conserve moisture; avoid smothering
A light mulch of grit or coarse gravel around plants helps retain moisture and suppress weeds without smothering the crown. Avoid organic mulch directly over the centre of the plant, especially in wet conditions, as this can cause crown rot.
Growing Tips
Poor soil is no problem
Blue eyed grass thrives in lean, well-drained soil. Avoid rich beds or heavy clay — poor drainage and excess fertility reduce flowering and shorten the plant's life. Gravel gardens and sunny slopes are ideal.
Deadhead to extend the season
Removing spent flowers regularly throughout spring and early summer encourages continuous blooming and prevents excessive self-seeding, which can become weedy in ideal conditions.
Allow some self-seeding for a natural colony
Blue eyed grass is short-lived but perpetuates itself readily through seed. Allow a few seedheads to develop each year to maintain the colony. Seedlings transplant easily when small.
Divide every two to three years
Clumps lose vigour as they age. Lift and divide in spring or early autumn, replanting the youngest outer sections. This also helps control the spread.
Pests & Diseases
Pest Slugs and Snails
Identification: Ragged or missing young shoots; silvery slime trails on foliage and soil
- Apply biological nematode control (Phasmarhabditis hermaphrodita) in early spring
- Use grit or sharp sand around clumps as a physical barrier
- Apply ferric phosphate slug pellets around emerging growth
Pest Spider Mites
Identification: Fine pale stippling on leaves; fine webbing on undersides in heavy infestations; leaves turn yellowish
- Mist foliage with water to raise humidity — spider mites hate moisture
- Introduce predatory mites (Phytoseiulus persimilis) in greenhouse settings
- Spray with a fatty acid or plant oil-based insecticide
Disease Crown Rot
Symptoms: Plant wilts and collapses from the base; crown feels soft and mushy; foliage yellows rapidly
Treatment: Remove and destroy affected plants; do not replant in the same spot without improving drainage
Prevention: Ensure excellent drainage; avoid overwatering; grow in gritty or sandy soil; do not mulch directly over the crown
Disease Rust
Symptoms: Orange or brown pustules on leaf undersides; upper leaf surface shows pale spots; leaves may die back prematurely
Treatment: Remove and destroy affected leaves promptly; improve air circulation
Prevention: Avoid overhead watering; ensure good plant spacing; remove dead foliage in autumn
Log Blue Eyed Grass in your garden — track growth, care, and harvests year after year
Start planning free