Macadamia : Macadamia spp.

Macadamian Nut Tree between Punalu’u and Kona


Taxonomy: Kingdom: Plantae; (unranked): Angiosperms; unranked): Eudicots; Order: Proteales; Family: Proteaceae; Genus: Macadamia; Species: various – some examples: Macadamia claudiensis, Macadamia grandis, Macadamia hildebrandii, Macadamia integrifolia Macadamia jansenii Macadamia ternifolia, Macadamia tetraphylla, Macadamia whelanii, Macadamia neurophylla, etc. Common names: Macadamia Nut, Bush Nut, Maroochi Nut, Queent of Nuts, Bauple Nut, Gyndl, Jindilli, Boombera, Macadamia, Australian nut, Queensland Nut.

One of the world’s most popular nuts, and prized in its incorporation with chocolate, it is most referred to as the nut of the Macadamie tree of the same name, from a variety of species under the Genus Macadamia of the Proteaceae family. The name of the tree and nut comes from being dedicated to the famous colleague “John Macadam” of botanist Ferdinand von Mueller who named the plant. Its a flowering tree that births a very hard nut. The trees are small to large evergreens that can grow to a height of 2-12 meters. Its leaves are arranged in whorls of 3-6 with lanceolate, obovate, or elliptical shapes, depending on the species. The leaves can grow to 6-30 cm long and 2-13 cm broad with an entire or spiny-serrated margin. The flowers produced by the tree come from long slendor simple racemes sprouting to 5-30 cm long with individual flowers from 10-15 mm long ranging in color from pink to purple and possessing 4 tepals. The fruit or seed is a very hard woody globose follicle with a pointed apex containing one or two seeds (the actual nut).

Very abundant in Australia, Macadamia has a long told history in the lands down under. M. integrifolia is native to SE Queensland where it grows in rain forests and near streams. M. tetraphylla is native to SE Queensland and NE New South Wales where it grows in rainforests and moist places along streams. Used by Australian aborigines for hundreds of years, the nut was first discovered by Europeans in 1828 by Allan Cunningham. It was named “Macadamia” by botanist Ferdinand von Mueller in 1857 after his friend. In 1858 a non-indigenous boy was noted eating the nut without ill effect, and scientists started to investigate its consumption properties. In the 1860’s the aboriginal elder known as King Jacky in Brisbane, Queensland, became the first known macadamia nut entrepreneur as his tribe regularly collected and traded the nuts with settlers. The first commercial orchard was planted in the early 1880’s by Charles Staff at Rous Mill in New South Wales. It was introduced to Hawaii and California in 1881 as an ornamental and reforestation – booming into a export nut business in later years. 1922 the Hawaiian Macadamia Nut Company in Hawaii was established. 1925 Hawaii gave birth to its first macadamia nut farm. 1937 it was discovered how to mass produce the nuts. The Hawaii macadamia industry boomed by 1948. Then in 1997 Australia surpassed the United States in nut production. In 2003 it was discovered that Macadamia Nuts lowers total and LDL cholesterol levels. Commercially important in Hawaii, California, Australia, Africa, and Central America as a valuable food crop. Only two of the species, Macadamia integrifolia and Macadamia tetraphylla are imported/exported in the food industry as most of the remainder of the species possess poisonous or inedible nuts as in the case with M. whelanii and M. ternifolia due to high presence of cyanogenic glycosides. Hawaii boomed the macadamia nut industry making it popular world-wide. Now produced commercially worldwide but primarily from Australia, South Africa, Brazil, California, Costa Rica, Israel, Kenya, Bolivia, New Zealand, Hawaii, and Malawa. Australia is the worlds largest producer.


While the Australia Aboriginals at the nuts often throughout their history, Macadamia wasn’t eaten by Western or European culture until 1858. Shortly after it was incorporated into culinary dishes. The Nuts need to be dehusked of the extremely hard shell and dried away from the sun for 2-3 weeks. The nuts are then baked (and stirred) in a shallow pan in an oven at the lowest temperature setting (100 degrees F) for 12 hours and then stored in cool and dry areas in the production process. In home use, Macadamia is primarily home-roasted in a shallow pan and roasted 40-50 minutes stirred occassionally then dried and stored in nicely, salted or unsalted airtight jars at 40-65 degrees Fahrenheit. But they are eaten raw or roasted as a snack and through the years added to stuffings, fruit salads, chocolates, cakes, and pies.


Very highly nutritious they are know to lower total and LDL cholesterol levels because they have the highest amount of beneficial mono-unsaturated fats of any known nut. They also contain 9% protein, 9% carbohydrate, 2% dietary fiber, calcium, phosphorus, potassium, sodium, selenium, iron, thiamine, riboflavin and niacin. Oil made from the nut contains 22% of the Omega-7 palmitoleic acid,[6] which makes it a botanical alternative to mink oil which is highly desirable ingredient in cosmetics, especially skin care and massage oils.


There are only two edible species, though many cultivars have been developed. Macadamias are suited to mild, frost-free climates with abundant rainfalls. The trees do best in full sun although hot climates with partial shade are beneficial. Windy locations should be avoided as trees are very susceptible to damage from winds. Mature trees are fairly frost hardy with toleration of temperatures as low as 24 degrees Fahrenheit but will lose the flowers at 28 degrees. Younger trees will be devastated even by light frosts. Consistent high temperatures however will reduce yields. Its propagated by grafting and is longer to mature to fruit bearing stages. Produces commercial quantities of nuts when it is 7-10 years old and can continue to bear nuts for over 100 years. The trees prefer fertile, well-drained soils with a rainfall of 1,000-2,000 mm and temperatures not falling below 10 degrees celsius. They have weak roots that are susceptible to storm damage as well as the phytophthora root disease. Since the nut has an extremely hard shell it is not easy to open. It requires being cracked by a blunt instrument such as rocks, hammers, or weights with force on the nut sitting in a concave surface. Because of this, custom-made nutcrackers have been created through time to burst them from their shell. Macadamias perform well in a wide range of soil types from open sand and lava rock soils to heavy clay. The soil does need to be well drained. They perform best in deep rich soils with 5.5-6.5 pH and little to no salt concentrations. They can withstand droughts but that will affect the harvest.

Other Uses:

The nuts have other uses outside of snacks and additions to meals and desserts. They are often fed to Hyacinth Macaws in captivity who are capable of cracking/shelling the nuts naturally. Trees are often used as ornamentals. The nuts chopped are used by law enforcement to simulate crack cocaine in drug stings.


The nuts however are toxic to a variety of animals, especially dogs, which can cause macadamia nut toxicosis inhibiting the inability to stand within 12 hours of ingestion, though they can recover within 48 hours. Only two species are edible, most of the others are toxic or too difficult to eat.


  • Garg, M.L., Blake, R.J., Wills, R.B. 2003 : “Macadamia Nut Consumption Lowers Plasma Total and LDL Cholesterol Levels in Hypercholesterolemic Men”. American Society for Nutritional Sciences Journal of Nutrition. 133: 1060-1063.
  • Power, J. 1982 : “Macadamia Power in a Nutshell”.
  • Wagner-Wright, Sandra. 1995. “History of the Macadamia Nut Industry in Hawai’i: 1881-1981.” (E. Mellen Press)

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