How to grow Macadamia in Australia
Macadamia is an Australian rainforest tree from south east Queensland and northern New South Wales, grown for its rich, buttery nuts. It crops best in a similar frost-free subtropical climate. In colder areas it often grows into a handsome shade tree that flowers but sets few nuts.
📖 Our full guide: How to Grow Macadamia in Australia
At a glance
When to plant by region
| Region | When to plant | Regional note |
|---|---|---|
| South East Queensland | March to September | |
| Northern Rivers NSW | March to September | |
| Sydney & Coastal NSW | March to September | |
| Melbourne & Victoria | September to November | Marginal. Plant Sep to Nov once frosts finish in mid September, in a warm sheltered spot, and use frost cloth while young. Fruiting is slow. |
| Adelaide & SA | September and October | Plant Sep to Oct in a warm sheltered spot and water deeply through summer. Plains gardens rarely frost; in the Adelaide Hills, use frost cloth while young. |
| Perth & WA | March to May, August to October | Plant in autumn or from late winter to early spring in a spot sheltered from strong wind. Mulch the sand heavily and water deeply through summer. |
| Tasmania | Not suited | Unsuitable. Too cold for reliable nut set. Not viable in Tasmania. |
| Canberra & ACT | Not suited | Not viable. Young trees are killed by hard frost; Canberra winters are too cold for reliable nuts. |
| North Queensland | May to September | Dry season establishment May to Sep, watering until the wet. Macadamia is a subtropical tree that needs cool nights to flower, so the Atherton Tableland suits it far better than the hot coast. |
| Darwin & Top End | May to September | Trial only. Plant May to Sep and water until the wet. Macadamia is a subtropical tree that needs cool nights to flower, and it has not cropped well this close to the equator. |
Where to plant
Plant in full sun in deep, well-drained soil, out of strong wind. Macadamias do best where it is frost free and days are warm, about 25 to 35°C, with plenty of rain, around 1000 mm a year, especially in summer. They grow in a wide range of soils, but improve sandy soil with plenty of compost. Wet, poorly drained ground leads to root rot.
Give the tree room. Left alone, a macadamia can grow up to 20 m tall and 10 m wide over 30 to 40 years, although it can be pruned to almost any height. Compact home varieties suit smaller yards.
- South East Queensland and the Northern Rivers: the macadamia's home climate, where backyard trees crop well.
- Sydney and Perth: grows well, but nut crops are lighter than in the subtropics. In Perth, mulch the sand heavily and water deeply through summer.
- Adelaide and Melbourne: marginal. Plant in spring in a warm, sheltered spot and cover young trees on frosty nights. Expect slow, light cropping.
- North Queensland: plant in the dry season and water until the wet arrives. Upland areas such as the Atherton Tablelands are closer to the macadamia's natural climate than the hot coast.
- Darwin: it can be grown, planting in the dry season, but it is well outside its natural subtropical range, so treat it as a trial.
- Canberra and Hobart: not suited; too cold for reliable nuts.
Choosing a variety
Buy a grafted tree of a named variety from a reputable nursery. It bears years earlier than a seedling and the nut quality is known. Varieties with an A in front of the number have thinner shells and more kernel. Two different varieties are not essential, but planting two gives a bigger crop.
- Beaumont (H695) is a popular backyard variety with pink flowers and easier-cracking nuts.
- Ask a local nursery which varieties crop well in your area.
How to plant
- Plant in the season that suits your region: autumn to spring in warm areas, or spring after frost in the south.
- Dig a wide hole the same depth as the pot, mixing compost into sandy soil.
- Plant at the same depth as in the pot, keeping the graft above the soil.
- Water in deeply and mulch widely, keeping mulch clear of the trunk. The surface roots like a thick mulch.
- In frost-prone areas, cover young trees on cold nights for the first few years.
Watering and feeding
Water young trees regularly while they establish. Established trees in high-rainfall areas often need no extra water, but water during dry spells, and where rainfall is under about 800 to 1000 mm a year. Water as soon as the flower strands appear and while nuts are filling, as flowers wilt and drop in dry weather.
Feed in autumn and spring with a fertiliser made for Australian native plants, which is low in phosphorus, spread under the tree out to the edge of the canopy and watered in. Compost or horse or cow manure also suit. Avoid chicken manure unless it is very well aged. Spreading grass clippings, chipped garden waste or old macadamia husks under the tree mimics the rainforest floor and improves the soil.
Pruning and care through the year
- Prune in May or June after harvest. Remove dead and inward-growing branches, then shape to the size you want. Start shaping early: take out the leader at a manageable height and let three or so side branches grow.
- Macadamias are pollinated by bees and other insects. Other flowering plants in the garden help bring pollinators in at spring flowering.
- Collect fallen nuts promptly, which keeps rats and nut borer down.
Harvesting
Nuts fall to the ground when mature, mainly between March and August, with most dropping in May and June. Pick them up as soon as they fall. Nuts still on the tree in spring can be picked by hand and are still good.
Remove the green husk straight away; if it sticks, leave the nuts in a warm spot for a week and try again. Dry the nuts in their shells slowly for a few days in a warm, dry place, ideally in the high 30s°C, such as a dehydrator or a north-facing windowsill. An oven gets too hot. Then crack them, as macadamias have the hardest shell of any nut and need a proper nutcracker or a hammer.
Using it
Crack the nuts first and roast the kernels afterwards, if you roast them. Store cracked kernels out of the sun in an airtight container or vacuum-sealed bag, in the fridge in warm areas, or freeze them. The hard shells and husks make a long-lasting mulch.
Pests and diseases
In backyards the main losses come from birds and rats taking the nuts, and from nut borer.
Pests to watch for
- Nut borer Holes in the husk and shell, with frass and damaged kernels. Pick up fallen nuts quickly; Trichogramma wasps are a biological control.
- Stink bug Bugs such as fruit spotting bug and green vegetable bug feed through the shell. Early feeding makes young nuts drop; later feeding leaves dark, sunken or shrivelled spots on the kernels.
- Rats Gnawed shells under the tree, especially near bushland. Collect nuts promptly and use bait stations if needed.
- Birds Cockatoos and galahs cracking green nuts on the tree.
Diseases to watch for
- Husk spot Pale yellow spots on the green husk of full-sized nuts that turn tan to dark brown, and nuts that drop before they are mature.
- Phytophthora Cankers and oozing bark near the base of the trunk, with a yellowing, thinning canopy, mostly in wet, poorly drained soil.
Common questions
How long does a macadamia tree take to produce nuts?
A grafted tree usually starts bearing from about its third or fourth year, with crops building over the following years. Seedling trees take longer and their nut quality varies.
Why is my macadamia tree not producing nuts?
The tree may be in a climate that is too cold, it may lack bees to pollinate the flowers, or the flowers may have been spoiled by rain at flowering or wilted in dry weather. If there are no flowers at all, feed with manure or a native plant fertiliser and water it in.
When are macadamia nuts ready to harvest?
When they fall from the tree, mostly between March and August with the peak in May and June. Pick them up promptly, remove the husks and dry them before cracking.
Can I grow macadamia in Melbourne or Adelaide?
The tree will grow in a warm, sheltered spot if young trees are protected from frost, but crops are usually light and slow. Macadamias are known for flowering more than fruiting in cooler climates.
How do I dry macadamia nuts?
Remove the husks, then dry the nuts in their shells slowly for a few days in a warm, dry place, ideally in the high 30s°C, such as a dehydrator or a sunny north-facing windowsill. Avoid the oven, which heats too fast.
How big does a macadamia tree get?
Left unpruned it can grow up to 20 m tall and 10 m wide over several decades. Regular pruning after harvest keeps it to almost any height, and compact varieties suit smaller yards.
Do I need two macadamia trees?
No, one tree will crop, but planting two different varieties usually gives more nuts.
Sources we checked: Australian Macadamias: Establishing a macadamia tree in your backyard; Australian Macadamias: So you want to grow your own macadamia tree? Six things to consider; Australian Macadamias: Caring for your backyard macadamia tree, your questions answered; Australian Macadamias: How to grow your own macadamias at home; Queensland DAF research (Plant Disease 91:12): husk spot of macadamia; WA DPIRD: Fruit spotting bug in macadamia; WA DPIRD: Green vegetable bug in macadamia.