How to grow kakadu plum
Overview
Kakadu plum (Terminalia ferdinandiana) is a small deciduous tree or large shrub native to northern Australia. It is prized for its small, tart fruits which contain the highest recorded natural vitamin C content of any food. Growers need to provide full sun and protection from frost for successful cultivation.
Soil Preparation
Kakadu plum prefers slightly acidic to neutral soil (pH 5.5-7.0) with good drainage. Sandy loam or well-drained clay loam is ideal. If planting in heavy clay, raise the bed or add gypsum and compost to improve drainage. Avoid waterlogged sites.
Growing Guide
Plant Kakadu plum in a sunny, well-drained position, ideally on a slight mound to improve drainage. Space trees 3-5 metres apart. Water deeply during establishment, then reduce to once weekly in dry periods. Apply a slow-release native fertiliser in early spring. Mulch with organic matter to 5cm depth, keeping clear of the trunk.
Sowing
Sow fresh seed 1-2cm deep in a seed-raising mix, keeping warm and moist. Germination takes 3-8 weeks. Seedlings are slow-growing; transplant when 15-20cm tall. Direct sowing is possible in tropical climates but requires protection from heavy rain and pests.
Care
Feed with a low-phosphorus native fertiliser in early spring and again in autumn. Prune lightly after harvest to remove dead wood and shape the canopy. Maintain a 5-10cm layer of organic mulch around the root zone, replenishing annually.
Companion Planting
Plant with other native fruiting trees like Davidson's plum, finger lime, and native raspberry for a diverse bush tucker garden. Avoid planting near eucalypts or acacias that may compete for moisture and nutrients. Keep away from heavy feeders like citrus that require different fertiliser regimes.
Common Pests & Risks
Fruit fly can be a problem in warmer regions; use netting or exclusion bags on developing fruit. Scale insects and mealybugs may appear on stems; treat with horticultural oil or neem spray. Leaf spot fungi can occur in humid conditions; improve air circulation and avoid overhead watering.
Harvesting
Harvest fruit when they fall to the ground or when they turn a pale yellow-green and soften slightly. Pick from late spring to early summer. Fruit can be collected from the ground, but do so promptly to avoid spoilage or insect damage.
In the Kitchen
The fruit is extremely tart and astringent, best used sparingly. It can be eaten fresh but is more commonly dried, powdered, or made into jams, sauces, and chutneys. The powder keeps for years in an airtight container and is used as a vitamin C boost in smoothies, desserts, and savoury dishes.
Troubleshooting
Yellow leaves: often caused by waterlogging or poor drainage; improve soil or move to a mound. Brown leaf edges: indicates salt burn or dry conditions; flush soil with fresh water and increase mulch. Fruit drop before ripe: may be due to fruit fly or sudden heat; net fruit and ensure consistent moisture. Slow growth: check for phosphorus toxicity from non-native fertiliser; switch to a native blend.