How to grow makrut lime in Australia

Like all citrus, makrut lime is best planted in the warmer half of the year once the soil has warmed and frost is behind you.

Tropical and subtropical (Darwin, Cairns, Brisbane): The ideal climate. Plant any time from spring through early autumn and it will grow strongly in the ground.

Warm temperate (Sydney, Perth, Adelaide): Plant in spring. It grows well here in a warm, sheltered, sunny position, ideally against a north-facing wall.

Cool temperate (Melbourne): Workable, but plant in spring and grow it in a pot you can move to a protected spot, or against a sheltered warm wall. Expect slower growth.

Cold (Hobart, Canberra, alpine): Too cold for open ground. Grow in a large pot and move it into a glasshouse, verandah or bright indoor spot over winter.

Arid (Alice Springs): Plant in spring in a spot with some afternoon shade and reliable water. It handles heat but resents dry roots.

Buy a grafted plant from a nursery rather than trying to grow from seed, since grafted citrus fruit sooner and grow more reliably. Plant into free-draining soil enriched with compost, at the same depth it sat in the pot, and never bury the graft union.

Citrus are hungry. Feed with a complete citrus fertiliser in late winter and again in summer, and mulch well while keeping the mulch back from the trunk. Water in thoroughly after planting and keep the root zone evenly moist through the first summer while it establishes.

Makrut lime is one of the best citrus for pots, which is exactly how most gardeners outside the subtropics grow it. Use a large pot, at least 40 to 50cm across, with a quality mix and excellent drainage, and pot up as it grows. The great advantage is portability: you can move it into sun in summer and under cover before the first frost.

In the ground it suits warm, frost-free gardens, where it forms a dense thorny shrub one to three metres tall. Give it a warm sheltered aspect and free-draining soil, and keep it pruned to a size you can harvest from easily.

Full sun gives the best leaf and fruit, ideally six or more hours a day, though it will cope with a little less. Shelter from cold wind matters as much as sun in cooler districts.

Water regularly and deeply, especially potted plants, which dry out fast in summer. Citrus dislike both drought and waterlogging, so aim for consistently moist but never soggy soil, and ease back a little in winter.

The leaves are the main crop and can be picked all year round. Take mature, fully expanded leaves as you need them, and light regular harvesting doubles as useful pruning. Leaves freeze well, so you can strip a handful and keep them in the freezer for months with little loss of aroma.

The fruit is knobbly and juice-poor, but the fragrant zest is used in cooking. Pick fruit when it colours up. Avoid stripping too much foliage from a young plant at once, as it needs leaf to build strength.

Makrut lime gets the same pests as other citrus. Watch for citrus leaf miner, which silvers and distorts new growth, citrus gall wasp causing swellings on stems, plus aphids, scale and sooty mould. Most are managed with horticultural oil, good hygiene and removing affected wood.

The biggest risk in cooler zones is frost, which burns leaves and can kill young plants, so protection over winter is the key job. As a citrus, the leaves and oils can cause mild upset if pets chew large amounts.

Underplanting citrus with flowering herbs such as borage and nasturtium can help draw in pollinators and beneficial insects, and a living mulch of low herbs keeps the root zone cool. Avoid planting competing shrubs right up against the trunk, and keep grass back from the base so the tree is not competing for water and feed.

Makrut lime is generally sold simply as makrut lime, without the range of named cultivars you see in eating citrus. When buying, choose a healthy grafted plant, and if you are in a cooler district look for one already established in a pot so it is ready to move under cover for its first winter.

Can I grow makrut lime in a pot?

Yes, and in cooler parts of Australia you should. A large pot lets you move it into full summer sun and then under cover before winter frosts, which is the main thing that kills young plants.

Do I use the leaves or the fruit?

Mostly the leaves, which carry the signature aroma and can be picked year round and frozen. The fruit is knobbly and low in juice, but its fragrant zest is also used in cooking.

Why is it called makrut lime now?

The older common name is widely regarded as an ethnic slur, so makrut lime (also sold as Thai lime) is the preferred term. It is the same plant, Citrus hystrix.