When to plant Rhubarb in Subtropical Australia

Subtropical zone — applies to Brisbane, Gold Coast, Sunshine Coast, Coffs Harbour, Lismore and similar areas. Growing elsewhere? Temperate · Cool · Tropical · Arid.

Rhubarb has a single narrow sowing window in the subtropical zone: sow direct in September, as the soil warms but before the summer wet builds. Germination is quick at 5–10 days from a 10 mm sowing, and plants need 100–140 days to produce stalks of usable size — though the first-year rule is to leave them unpicked while the crown builds strength. Rated frost tender, seedlings started in September also miss the light winter frosts that inland districts around Lismore can still get. Treat rhubarb as a challenge crop on the coast; it rewards good drainage more than any other input.

Sowing calendar — subtropical zone

Green months are your sowing window: September.

Growing notes

Rhubarb is a marginal proposition on the subtropical coast, and being honest about that shapes everything else. It is happiest where summers run cooler, so gardens in the hinterland behind the Gold Coast or the higher country inland of Lismore do noticeably better than sea-level Brisbane. The September sowing exists to give seedlings the entire mild spring to establish before the December to February wet, which is where subtropical rhubarb usually dies: warm, saturated soil rots the crown. Plant on a mound or raised bed with serious drainage, keep mulch clear of the crown itself, and choose a spot with morning sun and protection from harsh afternoon summer heat.

Expect stalks that are thinner and greener than the fat crimson supermarket stems — in warm climates, green-stalked rhubarb is normal and perfectly edible, though the leaves remain toxic and always go in the bin. Resist harvesting in the first year even though plants reach usable size within 100–140 days; letting the crown bank energy is what buys you a second season. When you do harvest, pull stalks with a twist at the base rather than cutting, and take no more than a third of the plant at once. Any plant that survives two subtropical summers has proven itself — treat it as a keeper worth dividing.

Rhubarb at a glance

Common questions

When do I plant rhubarb in the subtropical zone?

Sow direct in September, the only recommended month. That timing gives seedlings all of spring to establish before the humid summer wet season arrives.

Why did my rhubarb die over summer?

Crown rot in warm, waterlogged soil is the usual killer of subtropical rhubarb during the December to February wet. Grow it on a mound or raised bed with excellent drainage and keep mulch away from the crown.

Why are my rhubarb stalks green instead of red?

Green or partly green stalks are normal for rhubarb grown in warm climates and are perfectly edible — colour is about variety and temperature, not ripeness. The leaves, however, are toxic and should never be eaten.

Can I grow rhubarb in Lismore?

Yes, and the higher, cooler country inland does better than the coast. Sow in September, prioritise drainage, and skip harvesting in the first year so the crown establishes.

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