Dianella 'Clarity Blue'

Dianella 'Clarity Blue' (Dianella caerulea 'Clarity Blue') is the strappy native landscapers reach for when a planting has to look good with nobody looking after it. It forms a clumping tuft about 50cm tall and 50cm wide, with narrow blue-grey blades, sprays of small blue flowers and purple berries after them. It handles frost, drought, salt, heat and poor soil, which is a rare combination in one plant.

Why you'll love it

• It survives conditions that kill other groundcovers. Frost hardy, drought tolerant, salt tolerant, heat tolerant and happy in poor soil, all at once.
• Blue-grey foliage that holds colour. The cool tone stays consistent year round and contrasts well against green shrubs and dark mulch.
• Blue flowers, then purple berries. Airy flower sprays through spring and summer, then berries that native birds work through.
• Consistent size for repeat planting. A predictable 50cm by 50cm clump is what makes a mass planting read as one surface rather than a row of individuals.

Where it works best

Mass planting and groundcover. Plant 50cm apart for solid cover. At that spacing the clumps meet by the end of the second season and the planting reads as a continuous blue-grey surface.

Coastal gardens. Salt and heat tolerance make it one of the safer choices for exposed coastal beds and beachside verges, where it holds up in front of more sensitive shrubs.

Retaining walls, slopes and edging. The fibrous roots knit into a bank and help hold soil. Use the same 50cm spacing across the face.

Growing Dianella 'Clarity Blue' in Australia

Position and climate. Full sun brings out the strongest blue in the foliage, though it tolerates part shade with a looser, greener habit. It is at home across tropical, subtropical, warm temperate, cool temperate and arid gardens, and frost hardy once established.

Soil. Not fussy. Sandy, clay based and poor soils all work, provided water does not sit around the crown for days. Mulch 50mm deep and keep it clear of the centre of the clump.

Water and feed. Water weekly through the first summer to get the roots down, then it needs very little. A single application of low phosphorus native fertiliser in early spring is enough.

Maintenance. Every two or three years, shear the whole clump back to about 15cm in early spring. It reshoots quickly and comes back tighter. Remove spent flower stems any time they look untidy.

What to expect when it arrives

Clarity Blue is grown in two sizes: single tubes, and 140mm plants in packs of ten. Tube stock is a small tuft of a few blades, and the standard choice for large landscape jobs because dianellas establish fast and cost far less per square metre. The 140mm packs give you ten established clumps, enough for roughly 2.5 square metres at 50cm spacing.

Strappy plants travel well, though some blade tips may brown after transit. That is normal and grows out. Delivered Australia wide, with delivery from $29.95. Expect new blades within four to six weeks in warm weather and a closed planting by the second season. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• How to plant, space and maintain dianella
• Compare grasses and strappy leaf plants
• Plants chosen for large mass plantings
• More plants for exposed coastal gardens

Common questions

How many do I need per square metre?

At 50cm spacing you need four plants per square metre. Stretching to 60cm still closes over, it just takes an extra season, which is worth considering on a large job.

Does it need cutting back?

Not often. Shearing the clump to about 15cm every two to three years in early spring keeps it dense and removes the older, tired blades. It reshoots within a few weeks in warm weather.

Will it grow in shade?

It tolerates part shade, but the foliage greens up and the clump opens out. For the blue-grey colour that makes this selection worth choosing, give it full sun.