Macadamias are native to the subtropical areas of South East Queensland and northern NSW, so you’ll get best results – and more nuts – if you have subtropical conditions in your backyard.
A frost-free environment with a daytime temperature range of between 20-35ºC is ideal. Macadamia trees also need reasonable amounts of water (rainfall of at least 1000mm per year) but they can grow in a range of soils with the right care. Macadamias do grow in temperate zones (for instance, there’s a beautiful tree in the Royal Botanic Gardens in Sydney) but such trees are known for their spectacular flowers rather than their abundant nuts.
Macadamias grow into big trees – up to 20m high and 10m wide – so as well as a subtropical climate, you’ll need to ensure your backyard has enough space to accommodate the tree, or be prepared to prune it to size.
Reviving a backyard tree
It’s not uncommon for backyards in South East Queensland and northern NSW to have existing macadamia trees growing. Some of them simply need a little TLC to help them produce a bounty of nuts. If you have one in your garden that isn’t producing, take a look at our troubleshooting guides to help you work out what’s best for your tree.
Macadamia trees will generally grow without additional water or fertiliser. However, you may need to water your tree during dry spells or if you get less than 800mm per year in rainfall. Like most plants, macadamias will do better with the addition of native fertiliser applied during Autumn and Spring. Use a commercial product designed for native plants on the ground around the base of the tree where most of the roots are. A well-made garden compost, horse or cow manure will also be good for the tree, but avoid chicken manure unless it is very well aged.
To improve the general health of a neglected tree, try adding organic matter like grass clippings or mulch to the ground under the tree in a one metre radius from the trunk. This mimics the subtropical rainforest floor where wild trees get many of their nutrients. This will improve overall soil condition and help the tree’s roots retain moisture.