When to plant Lemon Balm in Subtropical Australia

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

Raise lemon balm from seed in September, October or November, sowing into trays and transplanting once seedlings are sturdy. The fine seed needs light to germinate, so press it onto the surface no deeper than 3 mm and expect a slow, uneven strike over 7–28 days. Plants reach usable size in 70–80 days and form a leafy, lemon-scented clump. Space them about 50 cm apart in rows 30–60 cm wide, as this hardy perennial spreads once settled. In Brisbane and Sunshine Coast gardens the spring sowing gives young plants a warm start before they establish into a long-lived herb.

Sowing calendar — subtropical zone

Green months are your sowing window: September to November.

Growing notes

Lemon balm is a hardy, easygoing perennial in the mint family, and it takes to the subtropics readily once past the fiddly germination stage. Give it a spot with morning sun and some afternoon shade, a soil kept lightly moist, and it will reward you with masses of lemon-scented leaves for tea, cooking and the odd calming brew. In the frost-free Gold Coast climate it stays green more or less year-round.

The seed is the tricky part, being small, slow and reliant on light, so many gardeners find it easier to start plants from a division or cutting off an established clump. Once you have a plant, propagation is trivial. The plant's other habit worth managing is spread: like its mint cousins it self-seeds and creeps, and in the warm humid climate it can colonise a bed quickly. Grow it in a pot or a confined bed, and cut off the flower heads before they set seed if you want to keep it in check.

In the humid wet season, watch for powdery mildew and rust on crowded plants. The fix is a hard cutback: shear the clump to near ground level, improve airflow, and let fresh, clean growth flush from the base. That same hard prune, done a few times a year in a Coffs Harbour garden, keeps the foliage young, tender and far more fragrant than leaves left to grow old and woody.

Lemon Balm at a glance

Common questions

How do I grow lemon balm from seed?

Sow the fine seed on the surface and barely cover it, as it needs light to germinate, then keep it warm and moist. Expect a slow, patchy strike over 7 to 28 days. Many gardeners find it easier to start from a division or cutting once they know someone with a plant.

Does lemon balm spread in the garden?

Yes, like other mints it self-seeds and creeps, and in the warm subtropics it spreads fast. Grow it in a pot or contained bed, and remove the flower heads before they set seed to keep it in check.

Why does my lemon balm get powdery mildew?

Crowded growth and wet-season humidity encourage mildew and rust. Cut the clump back hard to near ground level to open it up, and let clean new growth flush from the base. A few hard prunes a year keep the foliage fresh and fragrant.

Will lemon balm survive winter in Brisbane?

Yes, it is hardy and the frost-free subtropical winter suits it well, so it stays green more or less year-round. Growth slows in the cool months and picks up again in spring. A light feed and tidy in early spring gets it going.

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