How to Grow Blue Flax Lily
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Blue Flax Lily
Dianella caerulea
grassA hardy ornamental grass-like perennial native to Australia known for its strappy blue-green foliage and delicate blue flowers followed by striking cobalt-blue berries. It forms attractive clumps and provides year-round structural interest in gardens. The plant is evergreen in mild climates and offers excellent value as a low-maintenance landscape specimen.
When should you plant Blue Flax Lily in your zone?
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Example Blue Flax Lily timeline · Pittsburgh, PA (Zone 6b)
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Plant Blue Flax Lily
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Blue Flax Lily
Around Aug 15≈ 120 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Blue Flax Lily dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 8b-11, with best performance in zones 9-10
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Get my Blue Flax Lily timeline →Growth Stages
Establishment
4-8 weeksYoung plant with emerging strappy foliage, limited root system development
Keep soil consistently moist but not waterlogged. Provide afternoon shade in hot climates. Mulch around base to retain moisture.
Vegetative Growth
2-3 monthsClump expands with dense blue-green strap-like leaves reaching 12-18 inches tall
Maintain moderate watering during growing season. Remove any dead or damaged foliage. Feed with balanced fertilizer in spring.
Flowering
4-6 weeksDelicate pale to bright blue star-shaped flowers appear on thin stems above foliage
Flowers appear in late spring to early summer. Deadhead spent flowers if desired for tidier appearance, though berries will not form if removed.
Fruiting
8-12 weeksStriking cobalt to deep blue berries develop from spent flowers, persisting on plants for months
Allow flowers to remain for berry development. Berries attract birds and add ornamental value through fall and winter.
Dormancy/Maintenance
4-6 monthsPlant maintains evergreen foliage; growth slows in winter months
In colder zones, provide winter protection with mulch. Minimal watering needed. Remove winter-damaged foliage in spring.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with water to dislodge; use insecticidal soap if severe; increase humidity around plant
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Prune affected foliage; apply horticultural oil or insecticidal soap; inspect regularly
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and
Remove by hand; create barriers with copper tape; allow birds to forage nearby
Uses
Landscape accent and structure
OrnamentalBlue Flax Lily provides year-round architectural interest with its strappy foliage and striking blue berries. It works well in mixed borders, containers, and as a specimen plant in drought-tolerant gardens. [source]
Bird food and habitat
WildlifeThe abundant blue berries attract native birds and provide valuable food in fall and winter months. The dense clumping foliage offers shelter for small birds. [source]
Floral and dried arrangements
CraftBoth the blue flowers and cobalt berries are prized for fresh and dried flower arrangements, adding texture and striking color to bouquets and centerpieces. [source]
Edible berries
CulinaryThe blue berries are edible and reportedly have a slightly sweet flavor, though they are small and somewhat insignificant as a food source. Birds prefer them for consumption. [source]
Low-maintenance xeriscaping
HouseholdOnce established, Blue Flax Lily requires minimal water, fertilizer, or maintenance, making it ideal for drought-tolerant and water-wise garden designs. [source]
Harvest Tips
Berries can be harvested for dried arrangements when fully blue and firm (late summer to fall). Cut flowering stems for fresh arrangements when flowers are open. Foliage can be cut for structural elements in floral design year-round.
Fun Facts
- 🌱 The striking cobalt-blue berries remain on the plant for several months, providing ornamental value and food for birds long after flowering has finished.
- 🌱 Dianella caerulea is native to Australia and has been used in Aboriginal gardens for centuries; the name 'Dianella' derives from Diana, the Roman goddess.
- 🌱 The foliage of some Dianella cultivars contains saponins, which have been traditionally used in various cultures for natural soap and cleaning properties.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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