When to plant Rosemary in Tropical Australia

Tropical zone — applies to Darwin, Cairns, Townsville, Broome, Mackay and similar areas. Growing elsewhere? Temperate · Cool · Subtropical · Arid.

Rosemary has a narrow tropical window: raise seedlings in May or June — the coolest, driest part of the year — then transplant into the sharpest-draining spot you own. Sow 3 mm deep and allow 14 to 28 days for germination, which is erratic at the best of times. This is a long game; plants take around 365 days to reach maturity, so the real challenge in Townsville or Broome is not growing rosemary but carrying it alive through a wet season. Treat it as a container plant first and a garden shrub only if your site drains like a sieve.

Sowing calendar — tropical zone

Green months are your sowing window: May to June.

Growing notes

A Mediterranean shrub built for dry hillsides, rosemary meets its opposite in the monsoon, and humidity plus wet feet is the standard way tropical gardeners lose it. The plants that persist for years around Townsville and Broome are nearly always in large terracotta pots on gritty, free-draining mix, moved under a verandah or eave for the wet season, or planted on steep, sandy, elevated ground where storm water cannot pool for even a day.

Start from seed in May or June in trays of coarse propagating mix, keeping it barely moist — sodden trays rot seed that already needs 14 to 28 days to move. Given the slow, patchy germination and the year-long run to a mature plant, many growers sensibly begin from a cutting or nursery seedling instead and keep seed-raising as the purist's route. Plant out into full sun with generous space; mature bushes want around 150 cm, and cramming them against other plants traps the humid air that encourages fungal dieback.

Water deeply but rarely in the dry season, and not at all in the wet unless pots are under cover and bone dry. Skip rich soil and heavy feeding — lean conditions concentrate the oils that make rosemary worth growing. If a branch greys and dies back after rain, prune well below the damage immediately; dieback left in place keeps travelling.

Rosemary at a glance

Companion planting

Grows well with

Carrot: Volatile oils deter carrot fly

Broccoli: Deters cabbage white butterfly with volatile oils

Garlic: Both deter pests; garlic deters aphids, rosemary carrot fly

Common questions

When should I plant rosemary in tropical Australia?

Raise seedlings in May or June, the coolest and driest months, and transplant into a very well-drained position. Germination takes 14 to 28 days.

Why did my rosemary die in the wet season?

Waterlogged roots and constant humidity are fatal to rosemary. Grow it in a pot you can move under cover for the monsoon, or on elevated, sandy ground.

Can I grow rosemary in Townsville?

Yes, with drainage as the priority. Townsville growers do best with rosemary in large pots of gritty mix, sheltered from monsoon rain, rather than in garden beds.

How long does rosemary take to grow from seed?

Around a year to a mature, harvestable bush, after a slow 14 to 28 day germination. Cuttings or nursery plants are a much faster starting point.

Keep exploring