This species was formerly considered to be a part of Macadamia ternifolia[], it differs particularly in having a thinner shell around the seed[]. Some varieties of this species can produce nuts all year round, whilst Macadamia ternifolia is more seasonal[].

Common Name: Macadamia

General Information

Macadamia integrifolia is a very handsome, spreading evergreen tree with a dense crown[, ]. It can grow up to 15 metres tall[].
The tree is particularly valued for its edible seed, considered by many to be one of the most delicious seeds in the world[]. It is often planted for shade and ornament in the tropics, and is also cultivated for its edible seed in several tropical and sub-tropical areas, particularly Hawaii[, , ]. The seeds are traded internationally.

Known Hazards

None known

Botanical References

,

Range

Australia - New South Wales, Queensland

Habitat

Dry rainforests of the eastern coastal scrub[, ]. Found mainly on alluvial situations bordering rivers and creeks where the fertile volcanic soils are rich in humus[].

Properties

Edibility Rating
Other Uses Rating
Habit	Evergreen Tree
Height	15.00 m
Growth Rate	Slow
Pollinators	Bees
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Macadamia integrifolia is a plant of the subtropics and tropics of eastern Australia. Iit has fairly stringent environmental needs if good crops of seeds are to be produced[]. In the tropics it fruits best at elevations from 1,000 - 1,600 metres, but succeeds down to sea level in the subtropics[]. It grows best in areas where annual daytime temperatures are within the range 10 - 26°c, but can tolerate 8 - 35°c[]. Mature plants are capable of withstanding mild frosts, but only for short periods[]. It prefers a mean annual rainfall in the range 1,000 - 3,000mm, but tolerates 700 - 3,500mm[].
Requires a sunny position[]. Plants grow best in rich, moist but well-drained soils and require copious summer watering in their early stages[, ]. Prefers a pH in the range 5 - 6, tolerating 4.5 - 7[]. Established plants are very drought resistant[]. Trees require a sheltered position and are easily damaged by strong winds[].
Floral initiation takes place when temperatures drop and trees become quiescent in autumn, the optimum temperature being 18°c[]. The initials remain dormant for 50 - 96 days; the racemes extend after a rise in temperature and some rain[].
Seedling growth is initially slow, but gathers momentum as saplings produce a series of extension growth flushes in a year[]. The juvenile phase lasts for 7 years or more, but grafted trees come into bearing after 3 years[].
Plants are slow growing in cultivation, especially when young, seedlings take 6 - 7 years to produce their first fruit[, ]. The trees then produce commercial crops for about 40 - 50 years and can fruit for up to 100 years[].
The trees can flower and produce fruit all year round[].
Yields of 45 kg nuts-in-shell from better trees or an average of 3.2 - 3.5 t/ha per year are obtained in Hawaii[].
Pruning is not normally necessary, but is tolerated if carried out in the autumn[].
There are some named varieties[, ].

Edible Uses

Seed - raw or cooked. The fine, crunchy texture, rich cream colour and delicate flavour make the macadamia nut one of the finest dessert nuts[]. The eating quality of the nut is enhanced by lightly roasting it in coconut oil and salting[] .Sweet and delicious, the seeds can also be added to cakes, biscuits, ice cream etc[, ]. They can be ground into a flour and then added to cereals to enrich their protein value. The shell is very hard, making it difficult to extract the seed[]. The seed is up to 3cm long and wide[].

An edible oil can be obtained from the seed[], though it is seldom extracted due to the high value of the seed[] The seed contains the highest level of oil yet found in a nut - up to 75%[]. The oil contains 80% monounsaturated fats and 8% omega-6 fatty acids[]. It has a subtle, nutty flavour and is added to salads, used in cooking etc[].

Medicinal

None known

Agroforestry Uses:

The decomposed husk is commonly used in potting soil[, ].
Macadamia will retard the growth of papaya trees planted near to it[].

Other Uses

Macadamia shells may be used as fuel, generating sufficient energy to dry wet, in-shell nuts[].

The oil from the seed is used in cosmetics[].

The green seed hulls contain approximately 14% of tannins[].

Propagation

Seed - best sown as soon as it is ripe in a warm greenhouse[]. The dehusked seed germinates quickly at 25°c[]. The seed can also be sown in the spring in a warm greenhouse[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. If trying them outdoors, give the plants some protection from the cold for their first few winters.
Cultivars may be grafted.