When to plant Dianthus in Temperate Australia

Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.

Sow dianthus direct from February to November, taking advantage of its long temperate window and setting the fine seed just 3 mm deep. Germination takes 10–20 days, and plants are slow to flower, reaching bloom in around 140 days, so an autumn or late-winter sowing gives you flowers the following spring. Thin or space plants to about 20 cm apart with rows 20–30 cm apart, in full sun and well-drained, slightly limey soil. These hardy cottage flowers, including pinks and carnations, suit the mild conditions across temperate Adelaide, Melbourne and Perth.

Sowing calendar — temperate zone

Green months are your sowing window: February to November.

Growing notes

Dianthus is hardy and long-lived once established, but it is fussy about drainage and soil acidity. The classic failure is a plant that yellows, rots at the crown and dies over a wet winter; this comes from soggy, heavy soil. Grow it in free-draining ground, raise the bed if you have clay, and avoid mulching right up against the stems where damp collects.

Most dianthus prefer neutral to slightly alkaline soil, which is where the old name of the family comes from. If your soil is acidic, a light dressing of garden lime before planting helps plants settle and flower well. This suits many temperate gardens around Adelaide and Perth that already run to the alkaline side.

Seed is slow and the plants take their time, so be patient; sowing 3 mm deep and keeping the surface just moist gives the most even germination. Once flowering, deadhead regularly to extend the display, as spent blooms left on the plant slow further flowering.

Give dianthus full sun for the strongest flowering and to keep the foliage dry and healthy. In too much shade, plants grow soft, flop and become prone to fungal spotting. After the main flush, a light trim keeps the plants compact and encourages a second showing.

Dianthus at a glance

Common questions

when do you sow dianthus in Adelaide

In temperate Adelaide, dianthus can be sown direct from February right through to November. Autumn and late-winter sowings work well, giving plants time to establish before flowering the following spring, since they take around 140 days to bloom.

what soil does dianthus like

Dianthus prefers free-draining, neutral to slightly alkaline soil. It resents wet, heavy or acidic ground, which causes crown rot. If your soil is acidic, work in a little garden lime before planting to help it settle and flower.

why is my dianthus not flowering

The usual causes are too much shade, overly rich soil, or plants that are simply still young, as dianthus is slow to reach flowering. Give it full sun, avoid heavy feeding, and deadhead spent blooms to encourage more flowers.

is dianthus a perennial

Many dianthus, including pinks and carnations, are hardy short-lived perennials that flower for several seasons if grown in well-drained soil and full sun. A light trim after the main flush keeps them compact and prolongs their life.

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