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
Self-fertile	No
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 nursery bed[]. The dehusked seed germinates quickly at 25°c[].
Cultivars may be grafted. Side wedge grafting has been used exclusively in Hawaii[].

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