Q: What is an Indonesian lime?
A: Citrus aurantifolia is the small fruited lime also known as Key lime, Mexican lime or West Indian lime, and as Indonesian lime in parts of the Australian trade. The tree is small and thorny and the fruit is golf ball sized with thin skin, high acid and a much stronger aroma than the common Tahitian lime.
Q: Is Indonesian lime the same as Key lime?
A: Yes, they are the same species. Citrus aurantifolia is sold under a handful of names including Key lime, Mexican lime, West Indian lime and Indonesian lime, and the differences are naming conventions rather than distinct plants. Fruit, tree habit and growing requirements are the same whichever label it carries.
Q: How big does it grow?
A: It stays small, around 2 to 4 metres tall and 2 to 3 metres wide, and is often kept nearer 2 metres in a pot or with light annual pruning. The canopy is naturally twiggy and a little irregular rather than neatly rounded, and thinning it out occasionally improves both airflow and fruit quality.
Q: Is Indonesian lime frost tolerant?
A: No. It is the most cold sensitive citrus commonly grown and frost will damage or kill it, so it should not be planted in frost prone gardens. In cool temperate districts grow it in a large pot that can be shifted into a glasshouse, onto a verandah or against a warm wall from May to September.
Q: Can I grow it in a pot?
A: Yes, and in southern Australia a pot is usually the sensible approach. Use a container of at least 50 centimetres in a premium citrus mix, water more often than a garden tree and feed lightly through the warm months. Being movable lets you take it out of the cold, which is what determines whether it survives.
Q: Does it need another tree to fruit?
A: No. Citrus aurantifolia is self fertile and a lone tree will crop. It tends to flower in flushes rather than one clear season, so fruit often appears over a long window. Warmth is what drives cropping. In marginal climates the tree may flower well and still set only lightly.
Q: How do I look after an Indonesian lime?
A: Keep it warm, sunny and evenly watered, and never let a potted plant dry right out. Feed with citrus fertiliser in spring and midsummer. Prune only to open the canopy and remove dead twigs, wearing gloves for the thorns. Check regularly for citrus leaf miner, aphids and scale, which it is prone to.