Practical
Plants

Macadamia tetraphylla

Queensland Nut

a perennial woody evergreen member of the Macadamia genus in the family Proteaceae.

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Taxonomy and growth

Life cycle
perennial
Foliage
evergreen
Woodiness
woody
Growth rate
slow
Height
10 m
Spread
10 m
Fertility
Self fertile, Bees
Flower type
hermaphrodite
Pollinators
Bees

Uses

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Seed - raw or cooked[9][12][2]. Pleasantly flavoured and nutritious[1][13]. They can be eaten as a dessert nut and can also be ground into a flour and then mixed with cereal flours to enrich the protein content. The shell is very hard, making it difficult to extract the seed[11]. The seed contains up to 72% of a high grade oil[4].

Product or use
Oil
Plant part
Seed

Environment

Range
Australia - New South Wales, Queensland.
Habitat
In or near rainforests[6].
Light
full sun
Shade tolerance
no shade
Water
moderate
Hardiness
Zone 9+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Seed - best sown as soon as it is ripe in a warm greenhouse[8]. The dehusked seed germinates quickly at 25°c[10]. The seed can also be sown in the spring in a warm greenhouse[8]. 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.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Plants grow best in rich moist but well-drained soils and a position in full sun[3]. They require copious summer watering in their early stages[6]. Mature plants need at least 1250mm of rainfall equally distributed throughout the year and a mild frost-free climate[3]. Trees require a sheltered position and are easily damaged by strong winds[3][10]. Plants can be grown in climates cooler than their native habitat, but they are not very hardy in Britain. They produce fruit in Australia when growing at least as far south as Sydney[5]. They can survive slight frosts[10] and have succeeded outdoors in the Scilly Isles[1]. Growth is optimal between temperatures of 20 - 25°c, ceasing when they fall below 10°c or rise above 30°c[10]. Cold weather can result in the loss of the entire crop[10]. The macadamia nut is cultivated for its edible seed in many tropical and sub-tropical areas[6], there are some named varieties[6][7]. Plants are slow growing in cultivation, seedlings take 6 - 7 years to produce their first fruit[3][6]. The trees then produce commercial crops for about 40 - 50 years and can fruit for up to 100 years[10]. Plants are self-fertile but yield better if cross-pollinated[3]. Pruning is not normally necessary, but is tolerated if carried out in the autumn[8].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2

  2. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

    ↩

  3. Rosengarten. jnr. F. The Book of Edible Nuts. Walker & Co. 1984-00-00 ISBN 0802707699

    ↩1↩2↩3↩4↩5

  4. Cribb. A. B. and J. W. Useful Wild Plants in Australia. William Collins Pty Ltd. Sidney 1981-00-00 ISBN 0-00-216441-8

    ↩

  5. Wrigley. J. W. and Fagg. M. Australian Native Plants. Collins. (Australia) 1988-00-00 ISBN 0-7322-0021-0

    ↩

  6. Holliday. I. and Hill. R. A Field Guide to Australian Trees. Frederick Muller Ltd. 1974-00-00 ISBN 0-85179-627-3

    ↩1↩2↩3↩4↩5

  7. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

    ↩

  8. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩1↩2↩3

  9. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

    ↩

  10. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5↩6

  11. Phillips. R. & Rix. M. Conservatory and Indoor Plants Volumes 1 & 2 Pan Books, London. 1998-00-00 ISBN 0-330-37376-5

    ↩

  12. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩

  13. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩

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