Species

Dianella caeruleaBlue Flax-Lily

4 other cultivars

grass

Blue Flax Lily

Dianella caerulea 'King Alfred'

The Story

Plant Bio

Dianella caerulea is a clumping, evergreen herbaceous perennial native to eastern Australia, characterized by its tough, strap-like leaves and spreading underground rhizomes. The species produces airy panicles of small blue to purple flowers with prominent yellow anthers, followed by glossy, bright blue-purple berries.

'King Alfred' is distinguished by its compact, dense growth habit with short or absent upright canes and vivid red leaf sheaths at the base of its blue-green foliage. This cultivar exhibits exceptional tolerance to wind, salt, and brief periods of soil inundation compared to the straight species.

Uses & Benefits:

Provides year-round architectural structure with its blue-green, strap-like leaves and colorful spring flowers.

Excellent for stabilizing soil on banks and slopes due to its tough, spreading rhizomatous root system.

Provides pollen for native bees and nesting structure for ground-dwelling beneficial insects.

SpeciesDianella caeruleaBlue Flax-Lily

Essentials

At a Glance

Plant Type

Grass

Height

28"

Width

28"

Light

Full Sun, Partial Sun

Zones

8, 9, 10

Water

Low

Humidity

High

Lifespan

Long-lived perennial

Native To

Australia

Toxicity

Unripe berries are toxic

Bloom period

Mid-spring – Summer

In flower about 5 months of the year

Planting

How to Grow

Select a planting site in full sun to partial shade with well-drained soil, though heavy clay is also tolerated.
Dig a hole twice the width of the root ball and set the plant at the same depth it was growing in its container.
Water deeply and regularly during the first growing season to encourage the development of a deep, drought-tolerant root system.
Apply a light layer of organic mulch around the base to conserve moisture and suppress weeds, keeping it clear of the foliage crowns.

Pro Tip

To rejuvenate older, untidy clumps, cut the entire plant back cleanly to six inches above the ground; this triggers rapid, uniform new growth from the underground rhizomes.

Keep It Thriving

Care Guide

Do

Water thoroughly during prolonged dry spells to maintain optimal foliage color.
Prune damaged or dead leaves individually at the base to maintain a clean appearance.
Use a balanced slow-release fertilizer in spring if growing in highly depleted soils.

Don't

Do not overwater once established, as constantly soggy soil can lead to root rot.
Avoid planting in deep, heavy shade where the foliage will become lax and flowering will cease.
Do not allow livestock or pets to consume large quantities of unripe green berries.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Divide
Fertilize
Pest Check
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Erosion control on slopesMass plantings and bordersCoastal gardensContainer specimens

Companion Plants

Lomandra longifolia Westringia fruticosa Anigozanthos flavidus Salvia leucantha

Multiply

Propagation Methods

Good to Know

Common Questions

Blue Flax Lily questions

What zones can Blue Flax Lily grow in?

Blue Flax Lily is hardy in USDA Zones 8–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Blue Flax Lily deer resistant?

Not reliably. Deer may browse Blue Flax Lily, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Blue Flax Lily bloom?

Blue Flax Lily typically blooms in mid-spring through summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Blue Flax Lily need full sun?

Blue Flax Lily does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Blue Flax Lily drought tolerant?

Yes — once established (usually after the first full season), Blue Flax Lily handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.