How to grow mandarin
Overview
Mandarin (Citrus reticulata) is a compact, evergreen citrus tree grown for its fragrant white blossoms, glossy green leaves, and easy-peel, sweet fruit. It is one of the most productive and ornamental citrus for home gardens, thriving in warm, sunny positions with protection from frost.
Varieties
- Imperial — The most popular Australian mandarin, seedless, easy-peel, and very sweet, maturing in autumn.
- Murcott — A late-season variety with rich flavour and good storage, often called 'honey mandarin'.
- Ellendale — A classic Australian mandarin with a tangy-sweet taste, good for juicing, maturing mid-season.
- Afourer — A seedless, easy-peel variety from Morocco, maturing in late autumn, very popular in NZ.
Soil Preparation
Mandarin prefers a slightly acidic soil (pH 6.0-6.5), well-drained and rich in organic matter. Before planting, incorporate 2-3 kg of compost or aged manure per square metre, and add a handful of blood and bone. Improve drainage in heavy clay by mounding the bed or adding gypsum.
Growing Guide
Plant mandarin in a sunny, sheltered spot with well-drained soil, ideally a sandy loam. Space trees 3-4 metres apart, or 2 metres for dwarf varieties. Dig a hole twice as wide as the pot, backfill with compost and a slow-release citrus fertiliser, and water in well. Plant in autumn or early spring in temperate zones, avoiding winter wet in cooler areas. Stake young trees for the first year to establish a straight trunk.
Sowing
Mandarin is rarely grown from seed; most home gardeners buy grafted trees from nurseries. If sowing seed, plant 1 cm deep in seed-raising mix, keep at 20-25°C, and expect germination in 3-6 weeks. Seedlings take 5-7 years to fruit and may not be true to type.
Care
Feed mandarin with a balanced citrus fertiliser (e.g., 6-6-6) in early spring and late summer, plus a handful of sulphate of potash in autumn. Prune lightly after harvest to remove dead or crossing branches and maintain an open vase shape. Mulch with 5 cm of organic matter, keeping it 10 cm from the trunk to prevent collar rot.
Companion Planting
Plant mandarin with nasturtium, marjoram, and chives to repel aphids and attract beneficial insects. Avoid planting near eucalyptus or other citrus that host gall wasp; keep a 3-metre gap from lawns to reduce root competition.
Common Pests & Risks
Citrus gall wasp causes swollen galls on branches; prune out affected wood in winter and burn. Scale insects (soft and hard) can be controlled with horticultural oil in early spring. Leaf miner creates silvery trails; apply a systemic insecticide or use neem oil. Fruit fly can be managed with bait traps or netting after fruit sets.
Harvesting
Harvest mandarin when the fruit is fully coloured (orange or deep yellow) and tastes sweet, usually from late autumn to early spring. Pick by gently twisting the fruit from the stem; store at room temperature for up to a week or refrigerate for longer. Do not leave fruit on the tree too long after colouring, as it can become pithy.
In the Kitchen
Mandarin is best eaten fresh, but also excellent in salads, marmalade, and desserts. Store at room temperature for up to a week; refrigerate for 2-3 weeks. The zest can be dried or frozen for later use.
Troubleshooting
Yellow leaves: often caused by iron deficiency in alkaline soil; apply iron chelate. Brown leaf edges: usually from salt burn or overwatering; flush soil with water and reduce watering. Fruit splitting: due to uneven watering; maintain consistent moisture. Sooty mould: from scale honeydew; control scale and wash with soapy water. Poor fruit set: lack of pollination or cold damage; plant in a warm, sheltered spot.