How to grow longan
Overview
Longan (Dimocarpus longan) is a warm-climate evergreen fruit tree from the Sapindaceae family, prized for its sweet, translucent fruit. It thrives in humid subtropical and tropical regions, requiring full sun and consistent moisture during flowering and fruiting.
Varieties
- Kohala — Large, sweet fruit with small seed; reliable in subtropical QLD.
- Biew Kiew — Popular in Australia, heavy cropping with excellent flavour.
Soil Preparation
Longan prefers slightly acidic soil (pH 5.5–6.5) with good drainage. Amend heavy clay with gypsum and organic matter. Add compost and well-rotted manure before planting to boost fertility.
Growing Guide
Plant longan in full sun with well-drained soil, spacing trees 6–8 m apart. Dig a hole twice the root ball width, backfill with compost, and water deeply after planting. Maintain steady moisture, especially during flowering and fruit set, but avoid waterlogging. Mulch heavily with organic matter, keeping it clear of the trunk.
Sowing
Longan is rarely grown from seed as it takes 7–10 years to fruit and may not come true. Propagate by air layering or grafting. Seedlings need 2–3 years before transplanting.
Care
Feed longan with a balanced citrus or fruit tree fertiliser in early spring and again after harvest. Prune to an open vase shape in late winter to improve air flow and light. Keep mulch away from the trunk to prevent collar rot.
Companion Planting
Plant longan with other tropical fruit trees like mango, lychee, and jackfruit for a diverse orchard. Avoid planting near heavy feeders like bananas that may compete for nutrients. Keep away from eucalypts, which can inhibit growth.
Common Pests & Risks
Birds and bats are major pests, often stripping fruit before harvest. Net trees or use reflective tape. Mites cause leaf bronzing and fruit russeting; control with horticultural oil in early spring. Fruit flies can be a problem in coastal areas.
Harvesting
Harvest longan clusters when the skin turns tan-brown and the fruit is sweet, usually 3–5 months after flowering. Pick by cutting the stem with secateurs to avoid damaging branches. Fruit stores for 1–2 weeks in the fridge.
In the Kitchen
Longan is eaten fresh or canned. Peel and remove seed before adding to desserts, salads, or stir-fries. Store in fridge for up to 2 weeks.
Troubleshooting
Yellow leaves: often due to iron deficiency in alkaline soil; apply chelated iron. Brown leaf edges: caused by salt burn or dry winds; improve watering and mulch. Fruit drop: common from water stress or poor pollination; maintain even moisture. Poor fruit set: lack of chill or excessive nitrogen; reduce nitrogen in spring.