Cassa Blue™ Dianella

Cassa Blue Dianella (Dianella caerulea 'DBB03') is a compact clumping flax lily with rich blue foliage, about 50cm high and 40cm wide. Bred by Ozbreed, it is one of the longest flowering dianellas, sending up masses of baby blue flowers to about 55cm, and it takes drought and cold once established. In the southern states it is a mass planting workhorse; north of Sydney it is a plant for a well drained, cared for garden bed.

Why you'll love it

• Rich blue foliage. The leaf colour is a true blue grey rather than green, which lifts a native bed and pairs with silver and burgundy foliage.
• One of the longest flowering dianellas. Baby blue flowers on fine stems come in flushes through spring and summer, with purple berries after them.
• Compact and clumping. It stays at 50cm and does not run, so it holds its line along a path or in a drift.
• Drought and cold tolerant. Listed for Tasmania and the ACT as well as the mainland states, it handles frost and dry summers once established.
• Years between prunes. A cut back by half every three to five years is the only maintenance.

Where it works best

Mass planting in the south. Plant 40cm apart in offset rows, which gives about six plants per square metre, and the clumps meet within two seasons to form a dense blue carpet. In the ACT, Victoria, Tasmania, South Australia, Western Australia and from Sydney south, this is how it is used.

Maintained gardens north of Sydney. From Sydney north and in Queensland, Ozbreed recommends it only for maintained gardens with good, free draining soil, not for broadacre mass planting. In a mulched, raised bed it does well there; in a wet, neglected one it does not.

Specimen planting and edging. A single row at 40cm, two to four plants per metre, makes a blue edge along a path or a drive. Single clumps work in pots and small beds.

Growing Cassa Blue Dianella in Australia

Position and climate. Full sun to partial shade. It suits cool temperate, warm temperate and Mediterranean gardens outright, and subtropical gardens with the drainage caveat above.

Soil. Well drained soil, and drier soils in Sydney and anywhere humid. Avoid very poor soils, which starve it, and plant with the crown at soil level with mulch kept clear of the base.

Water and feed. Water as required for the first 8 to 13 weeks, then it manages on rainfall in the south. Mulch with a chunky mulch. A slow release fertiliser in spring is optional.

Pruning. Remove older leaves as they fade. Every three to five years cut the clump back by half in late winter; every three years keeps the foliage at its bluest.

What to expect when it arrives

We sell Cassa Blue Dianella in 140mm pots in packs of 10, the size that establishes fastest in a massed bed and the right quantity for a drift or a run of edging. Plants travel upright, settle within a few weeks and push new blue leaves from the centre of the clump in the first growing season.

Plants are delivered Australia wide, with delivery from $29.95. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Our dianella care guide
• Browse the full dianella range
• See the full Ozbreed range
• More plants for mass planting

Common questions

How far apart should I plant it?

Plant 40cm apart for a dense massed bed, up to 50cm where you can wait a second season for the clumps to meet.

Can I grow it in Queensland?

In a maintained garden bed with free draining soil, yes. It is not recommended for mass planting north of Sydney, where humid summers and wet soil cause losses.

Does it have berries?

Yes, small purple blue berries follow the flowers. They are decorative, and birds take them.