Practical
Plants

Eucalyptus globulus

Tasmanian Blue Gum

a perennial woody evergreen member of the Eucalyptus genus in the family Myrtaceae.

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Taxonomy and growth

Family
Myrtaceae
Life cycle
perennial
Foliage
evergreen
Woodiness
woody
Growth rate
vigorous
Height
55 m
Spread
15 m
Fertility
Bees
Flower type
hermaphrodite
Pollinators
Bees

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

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

Citronellal, an essential oil found in most Eucalyptus species is reported to be mutagenic when used in isolation[23]. In large doses, oil of eucalyptus, like so many essential oils has caused fatalities from intestinal irritation[23]. Death is reported from ingestion of 4 - 24 ml of essential oils, but recoveries are also reported for the same amount[23]. Symptoms include gastroenteric burning and irritation, nausea, vomiting, diarrhoea, oxygen deficiency, ,weakness, dizziness, stupor, difficult respiration, delirium, paralysis, convulsions, and death, usually due to respiratory failure[23]. The plant is reported to cause contact dermatitis. Sensitive persons may develop urticaria from handling the foliage and other parts of the plant[23].

Edible uses

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

An essential oil from the fresh or dried leaves is used as a flavouring in sweets, baked goods, ice cream etc[13][14].

Product or use
Condiment

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

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

Eucalyptus leaves are a traditional Aboriginal herbal remedy. The essential oil found in the leaves is a powerful antiseptic and is used all over the world for relieving coughs and colds, sore throats and other infections[22]. The essential oil is a common ingredient in many over-the-counter cold remedies[22]. The adult leaves, without their petioles, are antiperiodic, antiseptic, aromatic, deodorant, expectorant, febrifuge, hypoglycaemic and stimulant[24][29][16][25]. The leaves, and the essential oil they contain, are antiseptic, antispasmodic, expectorant, febrifuge and stimulant[18]. Extracts of the leaves have antibacterial activity[18]. The essential oil obtained from various species of eucalyptus is a very powerful antiseptic, especially when it is old, because ozone is formed in it on exposure to air. It has a decided disinfectant action, destroying the lower forms of life[24]. The oil can be used externally, applied to cuts, skin infections etc, it can also be inhaled for treating blocked nasal passages, it can be gargled for sore throat and can also be taken internally for a wide range of complaints[24]. Some caution is advised, however, because like all essential oils, it can have a deleterious effect on the body in larger doses[24]. The oil from this species has a somewhat disagreeable odour and so it is no longer used so frequently for medicinal purposes, other members of the genus being used instead[24]. An oleo- resin is exuded from the tree[19]. It can also be obtained from the tree by making incisions in the trunk[24][6]. This resin contains tannin and is powerfully astringent, it is used internally in the treatment of diarrhoea and bladder inflammation[24][6][19], externally it is applied to cuts etc[24][6]. The essential oil is used in aromatherapy. Its keyword is 'Respiratory system'[17].

Product or use
Antibacterial
Product or use
Antiperiodic
Product or use
Antiseptic
Product or use
Antispasmodic
Product or use
Aromatherapy
Product or use
Aromatic
Product or use
Deodorant
Product or use
Expectorant
Product or use
Febrifuge
Product or use
Hypoglycaemic
Product or use
Stimulant

Material uses

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

The leaves and the essential oil in them are used as an insect repellent[5][6][12][20]. The trees can also be planted in wet areas where mosquitoes abound. The ground will be dried out by the trees, making it unsuitable for the mosquitoes to breed[19]. A decoction of the leaves is used for repelling insects and vermin[23]. Africans use finely powdered bark as an insect dust[23]. An essential oil is obtained from the leaves[25][28][9]. It is used in perfumery and in medicines[1]. The yield is about 0.9% by steam distillation[7]. The essential oil is also in spot removers for cleaning off oil and grease[19]. Yields of 40 to 45 kilos of oil per hectare have been reported[23]. A yellow/brown dye is obtained from the young leaves. It does not require a mordant[11]. Grey and green dyes are obtained from the young shoots[11]. A dark green dye is obtained from the young bark[11]. Wood - heavy[25][28], (or light according to another report[10]), durable, fire resistant[8]. An important timber species, it is used for various purposes such as carpentry, construction, fences, piles, platforms, plywood, poles, sheds, tool handles and veneer[19][23]. The oil-rich wood is resistant to termites[23]. This is one of the best eucalypts for pulp production for making paper[6][23].

Product or use
Cleanser
Product or use
Dye
Product or use
Essential
Product or use
Fuel
Product or use
Repellent
Product or use
Wood

Environment

Range
Australia - Tasmania, Victoria.
Habitat
Damp marshy areas on moist loams and clays[30]. Found in hilly country or moist valleys in deep rich soils[10].
Light
full sun
Shade tolerance
no shade
Water
high
Hardiness
Zone 9+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerances
drought
Tolerates Nutritionally Poor Soil
No
Drought
tolerant

Propagation

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

Seed - surface sow February/March in a sunny position in a greenhouse[3][31][4]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[15]. Pot up the seedlings into individual pots as soon as the second set of seed leaves has developed, if left longer than this they might not move well. Plant out into their permanent positions in early summer and give them some protection from the cold in their first winter. The seed can also be sown in June, the young trees being planted in their final positions in late spring of the following year. The seed has a long viability[15].

Cultivation

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

Prefers a sunny position in a moderately fertile well-drained moisture retentive circum-neutral soil[15]. Succeeds in most soils[10], tolerating poor and dry soils, especially those low in mineral elements[15]. Established plants are drought tolerant[15]. Plants should not be grown in frost pockets or windy sites[2]. Requires a sheltered position, disliking cold, dry or desiccating winds[7]. Plants are reported to tolerate an annual precipitation of 80 to 160cm and an annual temperature range of ca 16 to 20°C[23]. This species is not very hardy in Britain, tolerating temperatures down to about -5°c[15] and often succumbing to heavy frosts[3][2][8]. There is a tree 35 metres tall on the Isle of Man, there are several taller trees in S. Ireland and a tree on the Isle of Wight was 20 metres tall when it was 9 years old from seed[3]. Eucalyptus species have not adopted a deciduous habit and continue to grow until it is too cold for them to do so. This makes them more susceptible to damage from sudden cold snaps. If temperature fluctuations are more gradual, as in a woodland for example, the plants have the opportunity to stop growing and become dormant, thus making them more cold resistant. A deep mulch around the roots to prevent the soil from freezing also helps the trees to survive cold conditions[15]. The members of this genus are remarkably adaptable however, there can be a dramatic increase in the hardiness of subsequent generations from the seed of survivors growing in temperate zones[15]. The Tasmanian blue gum is the most extensively planted eucalypt species in the world with a total of 800,000 ha in dozens of countries[23]. This species is commonly planted in S. Europe, especially in Italy, Spain and Portugal, for timber, soil stabilization and the essential oil in its leaves[27][28]. Trees have also been planted in marshy areas where they have the ability to reduce the wetness of the land (because they transpire so much water) thus getting rid of mosquitoes that were breeding there[24]. Eucalyptus monocultures are an environmental disaster, they are voracious, allelopathic and encourage the worst possible attitudes to land use and conservation[15]. A very fast growing tree, new growth can be up to 2.5 metres per year[3][26][2]. Trees are gross feeders and can severely stunt the growth of nearby plants[5]. Trees are very amenable to coppicing[26]. Plants are shallow-rooting and, especially in windy areas, should be planted out into their permanent positions when small to ensure that they do not suffer from wind-rock[21]. They strongly resent root disturbance and should be container grown before planting out into their permanent position[3]. The flowers are rich in nectar and are a good bee crop[11][15]. The bruised leaves emit a powerful balsamic smell[21]. This species is the national emblem of Tasmania[9][10].

References

  1. Polunin. O. Flowers of Europe - A Field Guide. Oxford University Press 1969-00-00 ISBN 0192176218

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  2. Brooker. M. I. A Key to Eucalypts in Britain and Ireland. HMSO 1983-00-00 ISBN 0-11-710192-3

    ↩1↩2↩3

  3. Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00

    ↩1↩2↩3↩4↩5

  4. Rice. G. (Editor) Growing from Seed. Volume 2. Thompson and Morgan. 1988-00-00

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  5. Holtom. J. and Hylton. W. Complete Guide to Herbs. Rodale Press 1979-00-00 ISBN 0-87857-262-7

    ↩1↩2

  6. Lassak. E. V. and McCarthy. T. Australian Medicinal Plants.

    ↩1↩2↩3↩4↩5

  7. Ewart. A. J. Flora of Victoria.

    ↩1↩2

  8. Arnberger. L. P. Flowers of the Southwest Mountains. Southwestern Monuments Ass. 1968-00-00

    ↩1↩2

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

    ↩1↩2

  10. 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

  11. Grae. I. Nature's Colors - Dyes from Plants. MacMillan Publishing Co. New York. 1974-00-00 ISBN 0-02-544950-8

    ↩1↩2↩3↩4

  12. Kariyone. T. Atlas of Medicinal Plants.

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  13. Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169

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

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  15. 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↩7↩8↩9↩10

  16. Lust. J. The Herb Book. Bantam books 1983-00-00 ISBN 0-553-23827-2

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  17. Westwood. C. Aromatherapy - A guide for home use. Amberwood Publishing Ltd 1993-00-00 ISBN 0-9517723-0-9

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  18. Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985-00-00 ISBN 0-917256-20-4

    ↩1↩2

  19. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

    ↩1↩2↩3↩4↩5

  20. Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement). Council of Scientific and Industrial Research, New Delhi. 1986-00-00

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  21. Genders. R. Scented Flora of the World. Robert Hale. London. 1994-00-00 ISBN 0-7090-5440-8

    ↩1↩2

  22. Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996-00-00 ISBN 9-780751-303148

    ↩1↩2

  23. Duke. J. Handbook of Energy Crops - 1983-00-00

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9↩10↩11↩12↩13

  24. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9

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

    ↩1↩2↩3

  26. Arnold-Forster. Shrubs for the Milder Counties.

    ↩1↩2

  27. ? Flora Europaea Cambridge University Press 1964-00-00

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

    ↩1↩2↩3

  29. Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984-00-00 ISBN 0-356-10541-5

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  30. Kelly. S. Eucalypts. (2 volumes.) Nelson, Melbourne 1969-00-00

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  31. Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00

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