Flax Lily Dianella Clarity Blue PBR

Clarity Blue is a flax lily grown for leaf colour, a cool blue-grey cast that holds through summer heat and reads clearly against rendered walls, concrete and dark mulch. The habit is clumping rather than running, with upright strappy leaves that stay where they are put, and it carries the small nodding blue flowers and blue-black berries typical of the genus. It goes into the hard places, mass planted through carpark islands, roadside verges and the baked strip beside a driveway.

Getting the spacing right before you order

It takes full sun to part shade, and the blue is strongest in full sun, while in part shade the foliage greens up and the habit softens. Water is low once established, soil can be poor as long as it drains, and it handles frost, reflected heat and coastal conditions. The failure mode here is not a pest or a disease, it is spacing, and it gets decided on the order form. Set the clumps too far apart and weeds own the bed for two seasons while they fill, which usually ends with someone spraying out the whole planting. Set them too close and they push against each other, open up through the middle and lose the clean line the planting was drawn for. Roughly four to six plants per square metre suits a bed, and tighter along a narrow verge strip where a continuous line is wanted sooner. Prepare the ground properly first, because the one chance to deal with weed seed and compaction is before the planting closes over. Low water is a property of an established root system, not a new plant, so keep water up through the first two summers.

Blue against green in mass planting

The nearest alternatives here are both softer in texture. Little Pal mat rush makes a fine, moving tuft that looks more like a garden plant than a civil one, and it is the pick where the planting sits close to a path and blue-grey would read as severe. Common tussock grass gives a meadow effect and tolerates ground that sits wet in winter, which Clarity Blue would rather avoid. Choose Clarity Blue when you want stiff upright form and a colour contrast that survives full sun and reflected heat. Both alternatives sit lower and read finer, so where the design needs some rigidity in the leaf, this is the one of the three to specify. More in flax lily.

Renovating a tired run of flax lily

There is no annual clipping. Leave it alone until the run starts to look tired, usually after several years, then cut the whole planting back low in late winter and water it through the regrowth, which is quicker and gives a more even result than picking over individual leaves. Feed after that cut with a low-phosphorus native fertiliser to push uniform regrowth. Snails and slugs will take the flower spikes in a wet spring. Note that this is a protected cultivar under plant breeders rights, so propagating your own plants from divisions is not permitted.

Choosing a size

This plant is available in 2 sizes, from 140mm up to 5L, priced from $17.95 to $30.95 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. These are younger plants, priced for planting in quantity, and they establish quickly once in the ground. Not sure which to choose? Read our guide to low water gardens.