Family: Myrtaceae
Common Name: Bloodwoods, Ghost Gums

Of the 113 species of Australian trees in this genus, many were formerly included in Eucalyptus and 33 are new species. The genus includes trees known as bloodwoods which are a major component of the flora of northern Australia and a significant component of woodland and forest floras in some more southern parts of that continent. The bloodwood group of trees is distinguished from some other eucalypts by its compound inflorescences, comprising numerous individual flowers in a dome-shaped group. The fruits (woody capsules or 'gumnuts') are generally urn-shaped, and sometimes rather large, and the hark peels off the trees in small, polygonal scales giving a tessellated appearance where it persists. The species described below are just a few of the more commonly cultivated members of this genus.

Species

Not all of these are readily available outside their native Australia.

C. calophylla (syn. Eucalyptus calophylla), the marri or red gum from Western Australia, is a variable tree from 12 to 25 m (40-80 ft), with a dense canopy. It generally flowers profusely in late summer and tall with conspicuous flowers that are usually white or cream but occasionally pink. It is very attractive to birds and bees when in flower so is useful for honey production. The red gum is used for large gardens, parks and shelter belts in its native state.

C. citriodora (syn. E. citriodora), lemon-scented gum, is one of the most frequently grown Australian trees. It reaches heights of 15-30 m (50-100 ft). Tall, straight, gray-white trunks and spreading, but not dense, canopies are characteristics of this tree. It is native to areas of far North Queensland but is adaptable to cultivation in a very wide range of soils and climates. The foliage is very strong smelling as it contains the essential oil citronella which is produced commercially.

C. ficifolia (syn. E. ficifolia), the red flowering gum from Western Australia, is generally seen as a fairly small tree of around 7-8 m (23-26 ft) outside its habitat where it grows from 6 to 15 m (20-50 ft). Good specimens flower profusely in summer in various shades of red, orange, pink or white, but it is almost impossible to predict flower color at an immature stage. However, seed saved from strong-colored flowers will often come true to type. It does very well in areas of low humidity and low or absent summer rainfall. It makes a delightful small tree for home gardens or for street plantings.

C. maculata (syn. E. maculata) is native to Queensland, New South Wales and Victoria. It is a tall tree, 20-30 m (65-100 ft) high, with a lovely trunk mottled with cream, blue and gray. Generally too large for home gardens, it is ideal for large parks or acreages. The canopy is often quite light allowing understorey plants to be grown successfully beneath it. If planted in very open situations, the crown becomes much wider and also shadier. The timber is hard and heavy with a range of commercial applications.

C. papuana (syn. E. papuana), ghost gum, is native to vast areas of tropical Australia. It is well known in Central Australia where its extremely white trunk makes a startling contrast to its surrounds. Height ranges from 10 m (33 ft) to more than 15 m (50 ft). In its variety of habitats it may be associated with rocky ridges or even fiat, sometimes marshy, ground. In the dry season it may be totally deciduous. This tree does not adapt to cultivation in temperate or coastal regions. The range of habitats is so diverse that seed should be collected from trees in the local area where it is to grow to ensure suitability.

C. ptychocarpa (syn. E. ptychocarpa), swamp bloodwood, from Western Australia and the Northern Territory, may grow to anywhere between 8 and 15 m (26-50 ft) tall, or even more. Although the tree shape may be straggly, the floral display is outstanding. Groups of flowers may be 30 or 40 cm (12-16 in) across, often weighing down the branches. The flowers may be pink, red or white, but all are attractive to honey-eating birds. The ribbed fruit which follow the flowers are also very' attractive. The leaves of this species are very large.

Cultivation

These trees are usually grown from seed, although some species are now being successfully raised from cuttings taken from the lignotuber, a storage organ just below ground level. Soil type and climatic requirements vary greatly between species, but there should be a species to suit every situation and district. Numerous species are grown in California and Arizona where they are a very common sight. In climatic zones below 9-10 grow as young foliage plants in pots or tubs it a cool, airy greenhouse or conservatory.

Climate

Zone 9-10.