Macadamia Farm

When in Hawaii last year, Don visited a macadamia farm. Although introduced to the world as the 'Hawaiian Nut', macadamias are actually Australian rainforest plants. They are members of the Proteaceae family, and are related to grevilleas and banksias. Long before Australia was settled by Europeans, macadamia nuts were eaten by Aborigines, who called the trees 'Kindal Kindal'. The genus was named in 1858 after the prominent scientist, Dr John Macadam.

Macadamia nuts are very hard to crack, and at first Australians did not consider them much of a commercial proposition. In about 1881 a man named William Purvis introduced macadamias to Hawaii, where they were grown mainly as ornamentals and for reforestation. Then in around 1924, the Hawaiians started to develop new varieties which produced better nuts that were easier to crack, and also the machinery to crack them.

Hawaiian varieties were imported back into Australia in the 1950s and 1960s.

Plant details

There are two species of macadamia which produce edible fruit, the smooth-shelled macadamia (Macadamia integrifolia) and the rough-shelled macadamia (M. tetraphylla). They grow to around 20m (60') in their natural habitat, but are much smaller in cultivation. M. integrifolia, which is native to south-eastern Queensland, is the commercially preferred species. It is an evergreen tree with glossy, dark green leaves in groups of three. In spring it produces sprays of creamy-white, fragrant flowers, followed by green fruit which ripens into hard-shelled, brown nuts. Fruiting varieties are normally grafted on M. tetraphylla rootstock. 'Kakea' and 'Keauhou' are two Hawaiian varieties grown in Australia.

Best climate

Macadamias grow best in warm, frost-free areas.

Uses

Macadamia nuts are delicious and healthy to eat raw or roasted. They do not contain cholesterol, and the oil contains 78% monounsaturated fats. Both oil and nuts can be used in salads, confectionery and cooking. The shells can be used in the manufacture of plastics, and the husks make a good addition to potting mixes. The trees can be grown as attractive ornamentals, as well as for their edible fruit.

Care

Macadamia trees need a warm, sheltered position, and like a well-drained soil enriched with compost. They are shallow-rooted, so need plenty of water, particularly during dry spells. Mulch to keep the roots cool and help prevent the soil drying out. Young trees should be protected from frost. When buying a macadamia for the home garden choose a grafted variety for best results.

Further information

For details about the Australian macadamia industry, visit the Australian Macadamia Society Ltd website: http://www.macsoc.com.au/

Copyright CTC Productions 2001