Common Name: Blue Mallee

General Information

Eucalyptus polybractea is an evergreen tree or large shrub that can grow up to 10 metres tall, usually with more than one main trunk[].
The tree is harvested from the wild for local use as a medicine and source of materials.It is sometimes cultivated in Australia for its essential oil[].

Known Hazards

None known

Botanical References

,

Range

Australia - Victoria, New South Wales

Habitat

Poor clayey and sandy soils in the semi-arid interior[]. Locally frequent but restricted, in sclerophyllous mallee shrubland on loamy soils[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	6.00 m
Growth Rate	Fast
Pollinators	Bees
Cultivation Status	Cultivated, Wild

Cultivation Details

Eucalyptus polybracteata is native to the semi-arid temperate climate of southeastern Australia, where it is found at elevations from 150 - 300 metres. Rainfall can occur all year round or only in winter, with a mean annual rainfall within the range 400 - 500 mm and a dry season that can be severe and last for up to 8 months. The mean maximum temperature of the hottest month is 30°c; mean minimum temperature of the coldest month is 3°c, and there are generally up to 10 frosts a year[].
Prefers a sunny position in a moderately fertile well-drained moisture retentive circum-neutral soil[]. Tolerates poor and dry soils, especially those low in mineral elements[]. Established plants are drought tolerant[].
The plant develops a lignotuber - this is a woody tuber that starts to develop near the base of seedlings and can become massive in the mature plants of some species. It possesses embedded vegetative buds, allowing the plant to regenerate following crown destruction, for example by fire[].
This species is cultivated in Australia for its essential oils[].
The leaves, when crushed, smell very strongly of eucalyptus[].
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[]. Many members of this genus are remarkably adaptable however, and there can be a dramatic increase in the hardiness of subsequent generations from the seed of survivors growing in temperate zones[].
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[]. They strongly resent root disturbance and should be container grown before planting out into their permanent position[].
Plants respond well to coppicing[].

Edible Uses

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

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

Agroforestry Uses:

The flowers are rich in nectar and are a good bee crop[].

Other Uses

The leaves yield up to 1.3% of essential oils with a high 1,8-cineole content (70 - 90%). It is used medicinally, in products such as toothpaste, mouth washes and cough drops, and as a food flavouring[, , , ]. The essential oil is an effective inhibitor of hydrochloric acid corrosion when coated over steel[].
The essential oil contains a very high proportion of the monoterpene ether 1,8-cineole (also known as eucalyptol). It has a fresh mint-like smell and a spicy, cooling taste. In low concentrations (0.002%) it is used as a flavouring in various products, including baked goods, confectionery, and beverages; it is used in perfumery and cosmetic products, for medicinal purposes and is also effective as a mosquito repellant[].

The wood is hard and strong. It was used traditionally for spear shafts[].
The wood is used as a fuel[].

Propagation

Seed - surface sow late winter/early spring in a sunny position in a greenhouse[, , ]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[]. 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 early summer, the young trees being planted in their final positions in late spring of the following year. The seed has a long viability[].