Dianella caerulea Cassa Blue ('Dbb03'PBR)

RHS Plant Profile
flax lily [Cassa Blue]

Synonyms

Dianella caerulea 'Dbb03'PBR

Herbaceous Perennial Grass Like

A compact, half-hardy evergreen perennial to 40cm high, with dense clumps of narrow, stiff, grass-like blue-green leaves. In early to mid summer, produces sprays of nodding light blue flowers with conspicuous yellow anthers, held on branched stems high above the foliage. These are sometimes followed by round blue-purple berries

Position

Full sun, Partial shade

Soil Types

Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity
2–5 years
Max Spread
0.1-0.5 metres
Max Height
0.5-1 metres

Growing Conditions

Loam Sand
Moisture
Well–drained
pH
Neutral or Acid

Position

Full sun Partial shade
Aspect
South–facing or West–facing
Exposure
Exposed or Sheltered
Hardiness
H3

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Asphodelaceae
Native to GB/Ireland
No
Foliage
Evergreen
Habit
Tufted, Clump forming
Potentially harmful
Fruit are ornamental - not to be eaten. Wear gloves and other protective equipment when handling
Genus
Dianella are rhizomatous evergreen perennials with leathery, sword-shaped leaves and sprays of small, starry deep blue flowers followed by long-lasting blue or purple berries
Name Status
Trade

How to Grow

Cultivation

In milder areas, grow outdoors in moderately fertile, well-drained, neutral to acid soil in full sun or partial shade. In areas prone to hard frosts, grow under glass in peat-free, loam-based compost, in full light with shade from hot sun. Water well in growth and keep just moist in winter.

Propagation

Propagate by division of rhizomes in mid-spring

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Coastal
  • Patio and container plants
  • Flower borders and beds
  • Conservatory and greenhouse

Pruning

No pruning required

Pests

Generally pest-free

Diseases

Generally disease-free