When to plant Rosemary in Cool Australia

Cool zone — applies to Hobart, Canberra, Ballarat, Orange, Armidale and similar areas. Growing elsewhere? Temperate · Subtropical · Tropical · Arid.

Raise rosemary from seed in November or December in the cool zone, transplanting seedlings once they are sturdy. This is a long game: germination is slow and patchy at 14–28 days, and a seedling takes a full year — 365 days — to become a properly harvestable shrub. Sow 3 mm deep in punnets kept warm and barely moist. Once established, rosemary is hardy enough for Canberra and Orange frosts; what kills it in cold districts is almost never the cold itself but wet feet through winter. Plan for its adult size from day one, allowing up to 150 cm per plant.

Sowing calendar — cool zone

Green months are your sowing window: November to December.

Growing notes

Rosemary earns its hardy rating in the cool zone with a caveat every Ballarat and Armidale gardener learns eventually: it tolerates frost, but not frost plus waterlogged clay. A mature bush shrugs off −5 °C mornings in free-draining soil, while the same plant in a soggy low spot quietly rots at the roots over winter and collapses in spring. Drainage is the whole game — plant on a mound or raised bed, work in coarse grit rather than rich compost, and skip winter watering entirely.

The November–December sowing window is about warmth for germination, which is slow and uneven at 14–28 days even in ideal conditions. Sow more seed than you need, keep punnets warm, and pot on the strongest few. Seedlings from a December sowing should be well rooted before their first winter; keep first-year plants in pots somewhere sheltered if your site is exposed, planting out the following spring.

Position is full sun, the more baking the better, with air movement around the foliage — cramped, humid corners breed fungal problems. Being at maturity 365 days from sowing, resist harvesting more than tips in the first year. After that, prune lightly but regularly after flowering; old wood cut back hard often refuses to reshoot, another common way cool-climate rosemary is lost.

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 sow rosemary seed in a cool climate?

Sow in November or December, raising seedlings in punnets for transplanting. Germination takes 14–28 days and is often patchy, so sow generously.

Why did my rosemary die over winter?

In cool-zone gardens the usual killer is winter wet, not frost — rosemary is hardy but rots in waterlogged soil. Replant in a raised or mounded position with gritty, free-draining soil and do not water in winter.

How long does rosemary take to grow from seed?

About a year to a genuinely harvestable shrub. Take only light tip pickings in the first season while the plant establishes.

How far apart should rosemary be planted?

Allow up to 150 cm per plant with 90–150 cm between rows — it becomes a substantial shrub, and good airflow around it prevents fungal trouble.

Keep exploring