Eucalyptus globulus
| Eucalyptus globulus | |
| Light: |  |
| Moisture: |    |
| Hardiness: | 9 |
| Soil pH: | 5.6-8.4 |
| Evergreen | |
| Height: | 180' |
| Width: | 49' |
| Speed: | Fast |
| Blooms: | Mid Summer-Late Summer |
| Open Woods Forest | |
| Native to: | |
| Edible Rating: |  |
| Medicinal Rating: |  |
| Tea: | Yes |
 | |
Eucalyptus globulus (common name: tasmanian blue gum)
Propagation: Seed - surface sow February/March in a sunny position in a greenhouse[1][2][3]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[4]. 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[4].
Cultivation: Prefers a sunny position in a moderately fertile well-drained moisture retentive circum-neutral soil[4]. Succeeds in most soils[5], tolerating poor and dry soils, especially those low in mineral elements[4]. Established plants are drought tolerant[4]. Plants should not be grown in frost pockets or windy sites[6]. 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[8].
This species is not very hardy in Britain, tolerating temperatures down to about -5°c[4] and often succumbing to heavy frosts[1][6][9]. 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[1].
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[4]. 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[4].
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[8]. 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[10][11]. 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[12]. Eucalyptus monocultures are an environmental disaster, they are voracious, allelopathic and encourage the worst possible attitudes to land use and conservation[4].
A very fast growing tree, new growth can be up to 2.5 metres per year[1][13][6]. Trees are gross feeders and can severely stunt the growth of nearby plants[14]. Trees are very amenable to coppicing[13].
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[15]. They strongly resent root disturbance and should be container grown before planting out into their permanent position[1].
The flowers are rich in nectar and are a good bee crop[16][4]. The bruised leaves emit a powerful balsamic smell[15].
This species is the national emblem of Tasmania[17][5].
Range: Australia - Tasmania, Victoria.
Habitat: Damp marshy areas on moist loams and clays[18]. Found in hilly country or moist valleys in deep rich soils[5].
Edibility: An essential oil from the fresh or dried leaves is used as a flavouring in sweets, baked goods, ice cream etc[19][20].
Medicinal: 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[21]. The essential oil is a common ingredient in many over-the-counter cold remedies[21].
The adult leaves, without their petioles, are antiperiodic, antiseptic, aromatic, deodorant, expectorant, febrifuge, hypoglycaemic and stimulant[12][22][23][24].
The leaves, and the essential oil they contain, are antiseptic, antispasmodic, expectorant, febrifuge and stimulant[25]. Extracts of the leaves have antibacterial activity[25]. 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[12]. 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[12]. Some caution is advised, however, because like all essential oils, it can have a deleterious effect on the body in larger doses[12]. 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[12].
An oleo- resin is exuded from the tree[26]. It can also be obtained from the tree by making incisions in the trunk[12][27]. This resin contains tannin and is powerfully astringent, it is used internally in the treatment of diarrhoea and bladder inflammation[12][27][26], externally it is applied to cuts etc[12][27].
The essential oil is used in aromatherapy. Its keyword is 'Respiratory system'[28].
Usage: The leaves and the essential oil in them are used as an insect repellent[14][27][29][30]. 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[26]. A decoction of the leaves is used for repelling insects and vermin[8]. Africans use finely powdered bark as an insect dust[8].
An essential oil is obtained from the leaves[24][11][17]. It is used in perfumery and in medicines[31]. The yield is about 0.9% by steam distillation[7]. The essential oil is also in spot removers for cleaning off oil and grease[26]. Yields of 40 to 45 kilos of oil per hectare have been reported[8].
A yellow/brown dye is obtained from the young leaves. It does not require a mordant[16].
Grey and green dyes are obtained from the young shoots[16].
A dark green dye is obtained from the young bark[16].
Wood - heavy[24][11], (or light according to another report[5]), durable, fire resistant[9]. An important timber species, it is used for various purposes such as carpentry, construction, fences, piles, platforms, plywood, poles, sheds, tool handles and veneer[26][8]. The oil-rich wood is resistant to termites[8]. This is one of the best eucalypts for pulp production for making paper[27][8].
Pollinators: Bees
Soil: Can grow in light, medium, and heavy soils.
Drainage: Prefers well drained soil.
In Leaf: Evergreen
Flower Type: Hermaphrodite
Known Hazards: Citronellal, an essential oil found in most Eucalyptus species is reported to be mutagenic when used in isolation[8].
In large doses, oil of eucalyptus, like so many essential oils has caused fatalities from intestinal irritation[8]. Death is reporte
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References
- ↑ 1.0 1.1 1.2 1.3 1.4 Bean, William. Trees and Shrubs Hardy in Great Britain. Murray, 1981.
- ↑ Sheat, Wilfrid. Propagation of Trees, Shrubs and Conifers. St Martin, 1948.
- ↑ Rice, Graham. Growing from Seed Volume 2. Thompson and Morgan, 1988.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ 5.0 5.1 5.2 5.3 Holliday, Ivan and Ron Hill. A Field Guide to Australian Trees. Frederick Muller, 1974.
- ↑ 6.0 6.1 6.2 Brooker, M. A Key to Eucalypts in Britain and Ireland. HMSO, 1983.
- ↑ 7.0 7.1 Ewart, Alfred. Recording Census of the Victorian Flora. 1923.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 Duke, James. Handbook of Energy Crops. 1983.
- ↑ 9.0 9.1 Arnberger, Leslie. Flowers of the Southwest Mountains. Southwestern Monuments, 1968.
- ↑ Tutin, Tom et al.. Flora Europaea. Cambridge University Press, 1964.
- ↑ 11.0 11.1 11.2 Usher, George. A Dictionary of Plants Used by Man. Constable, 1974.
- ↑ 12.0 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 Grieve, Margaret. A Modern Herbal. Penguin, 1984.
- ↑ 13.0 13.1 Arnold-Forster, William. Shrubs for the Milder Counties.
- ↑ 14.0 14.1 Hylton, Josie and William Holtom. Complete Guide to Herbs. Rodale Press, 1979.
- ↑ 15.0 15.1 Genders, Roy. Scented Flora of the World. Robert Hale, 1994.
- ↑ 16.0 16.1 16.2 16.3 Grae, Ida. Nature's Colors. MacMillan Publishing, 1974.
- ↑ 17.0 17.1 Cribb, Alan. Useful Wild Plants in Australia. William Collins, 1981.
- ↑ Kelly, Stan. Eucalypts. Nelson, 1969.
- ↑ Kunkel, Günther. Plants for Human Consumption. Koeltz Scientific Books, 1984.
- ↑ Facciola, Stephen. Cornucopia - A Source Book of Edible Plants. Kampong Publications, 1990.
- ↑ 21.0 21.1 Chevallier, Andrew. The Encyclopedia of Medicinal Plants. Dorling Kindersley, 1996.
- ↑ Chiej, Roberto. Encyclopaedia of Medicinal Plants. MacDonald, 1984.
- ↑ Lust, John. The Herb Book. Bantam Books, 1983.
- ↑ 24.0 24.1 24.2 Uphof, Johannes. Dictionary of Economic Plants. Weinheim, 1959.
- ↑ 25.0 25.1 Duke, James and Edward Ayensu. Medicinal Plants of China. Reference Publications, 1985.
- ↑ 26.0 26.1 26.2 26.3 26.4 Bown, Deni. Royal Horticultural Society Encyclopaedia of Herbs and Their Uses. Dorling Kindersley, 1995.
- ↑ 27.0 27.1 27.2 27.3 27.4 Lassak, Erich and Tara McCarthy. Australian Medicinal Plants.
- ↑ Westwood, Christine. Aromatherapy - A Guide for Home Use. Amberwood Publishing, 1993.
- ↑ Kariyone, Tatsuo. Atlas of Medicinal Plants.
- ↑ Chopra, R. Glossary of Indian Medicinal Plants. Council of Scientific and Industrial Research, New Delhi, 1986.
- ↑ Polunin, Oleg. Flowers of Europe. Oxford University Press, 1969.