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Plants

Eucalyptus polybractea

Blue Mallee

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
6 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[9]. In large doses, oil of eucalyptus, like so many essential oils has caused fatalities from intestinal irritation[9]. Death is reported from ingestion of 4 - 24 ml of essential oils, but recoveries are also reported for the same amount[9]. 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[9].

Edible uses

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

An essential oil from the leaves is used as a food flavouring in baked goods, ice cream and sweets[5].

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[8]. The essential oil is a common ingredient in many over-the-counter cold remedies[8]. The essential oil obtained from the leaves is antirheumatic, antiseptic and expectorant[10][3][4]. This is one of the main species used for its medicinal oils, which contain up to 85% eucalyptol[10]. 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[10]. 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[10]. Some caution is advised, however, because like all essential oils, it can have a deleterious effect on the body in larger doses[10].

Product or use
Antirheumatic
Product or use
Expectorant

Material uses

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

The leaves yield up to 1.3% of an essential oil. It is used medicinally and as a food flavouring[3][4]. The wood is used as a fuel[4].

Product or use
Essential
Product or use
Fuel

Environment

Range
Australia - New South Wales, Victoria.
Habitat
Poor clayey and sandy soils in the semi-arid interior[3]
Light
full sun
Shade tolerance
no shade
Water
high
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[1][11][2]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[6]. 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[6].

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[6]. Tolerates poor and dry soils, especially those low in mineral elements[6]. Established plants are drought tolerant[6]. This species is cultivated in Australia for its essential oils[10]. It is of very doubtful hardiness in Britain, though it might succeed outdoors in the mildest areas of the country[6]. 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[6]. 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[6]. Eucalyptus monocultures are an environmental disaster, they are voracious, allelopathic and encourage the worst possible attitudes to land use and conservation[6]. 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[7]. They strongly resent root disturbance and should be container grown before planting out into their permanent position[1]. Plants respond well to coppicing[4]. The flowers are rich in nectar and are a good bee crop[6].

References

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

    ↩1↩2

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

    ↩

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

    ↩1↩2↩3

  4. Ewart. A. J. Flora of Victoria.

    ↩1↩2↩3↩4

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

    ↩

  6. 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

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

    ↩

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

    ↩1↩2

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

    ↩1↩2↩3↩4

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

    ↩1↩2↩3↩4↩5↩6

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

    ↩

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