Macadamia integrifolia
Common Name: macadamia nut 
Type: Broadleaf evergreen
Family: Proteaceae
Native Range: New South Wales
Zone: 9 to 11
Height: 30.00 to 50.00 feet
Spread: 20.00 to 40.00 feet
Bloom Time: Seasonal bloomer
Bloom Description: White to pinkish-white
Sun: Full sun
Water: Medium to wet
Maintenance: Low
Suggested Use: Shade Tree
Flower: Showy
Leaf: Evergreen
Fruit: Showy, Edible
Other: Winter Interest

Culture

Winter hardy to USDA Zones 9-11 where it is best grown in rich, well-drained soils in full sun. Prefers consistent rainfall of at least 50" per year. Site in locations protected from strong winds. Drought tolerant once established. Intolerant of frost.

Noteworthy Characteristics

Macadamia integrifolia, commonly called macadamia nut, is a large, spreading broadleaf evergreen tree that typically grows to 30-50' tall. It is native to rainforests in southeastern Queensland, Australia. Macadamia nuts were a food source for aborigines long before Europeans first visited Australia. This tree was first introduced to Hawaii in 1837. Glossy oblong-lanceolate to oblong-ovate leaves (to 8-10" long) usually in whorls of three have slightly wavy margins. Sweetly fragrant, white to pinkish-white flowers (each to 1/2" long) in narrow drooping axillary racemes (to 8" long) bloom in winter and spring. Flowers are followed by the nuts. Each creamy white nut is encased in a hard, smooth, shiny shell. Shells are so hard that they cannot be opened by hand nutcrackers. Commercial fruits are opened by powerful husking machines. Although macadamia is native to Australia, Hawaii generally receives credit for developing the macadamia nut industry. Two species of macadamia nuts are commercially grown today: M. integrifolia (smooth-shell type) and M. teteraphylla (rough-shell type). Nuts commercially produced in Hawaii are from M. integrifolia which is by far the most commonly cultivated type. No other U.S. State has any significant commercial production, with the possible exception of California. Nuts produced in California are rough-shell types (M. tetraphylla).

Genus name honors John Macadam (1827-1865), chemist, medical man and lecturer in Melborne, Australia.

Specific epithet means with entire or uncut leaves.

Problems

No serious insect or disease problems.

Garden Uses

Commercially grown for production of macadamia nuts. Trees are ornamentally grown as shade trees with attractive spring flowers.