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Callistemon
Credits
Article from New Trees by John Grimshaw & Ross Bayton
Recommended citation
'Callistemon' from the website Trees and Shrubs Online (treesandshrubsonline.
Family
- Myrtaceae
Common Names
- Bottlebrushes
Synonyms
- Melaleuca R.Br.
The 35 species of Callistemon are endemic to Australia; the genus is closely related to Melaleuca L. (Brown, Udovicic & Ladiges 2001) and has been transferred into it by Craven (2006), though this is not universally accepted – see the genus entry for Melaleuca for a discussion of the taxonomy. They are spreading shrubs or small trees with stiff, evergreen foliage. The leaves are alternate, entire, sessile or shortly petiolate; immature growth is often pinkish red and usually covered in silky hairs. The flowers are sessile and amassed along the stem in several parallel rows, forming the ‘bottlebrush’; the stem continues to grow before or after flowering, producing a leafy shoot beyond the inflorescence. The flowers are hermaphrodite and 5-merous; the sepals circular, fused to the bell- or urn-shaped hypanthium; the petals circular, longer than the sepals, greenish yellow, white, pink or purple; the stamens numerous, conspicuous, much longer than the petals, free (not in bundles as in Melaleuca), white, cream, yellow, pink, mauve, red or purple. The fruit is a sessile, woody capsule that may persist on the plant for many years; fire may be the stimulus that causes the capsules to open (Elliot & Jones 1982, Mitchem 1993, Spencer & Lumley 2002).
Callistemon is another genus to have benefited in recent years from both the warmer climate and the greater inclination of gardeners to experiment, as several species and cultivars are now frequently to be seen in both public and private gardens throughout the United Kingdom. Many of these are short shrubby taxa, and few have achieved great size as yet, but the caution with which Bean (1976a) tentatively discussed them would not need to be repeated in a modern reference. They add a great deal of interest to the summer garden and are a welcome addition to the normal horticultural landscape, not only for the British Isles but for anywhere in milder parts of western Europe and the American West Coast. Few, however, form trees in our area, and of taxa not described by Bean, only C. viminalis is of tree-stature in its wild habitats. A warm, dry situation will give Callistemon the best chance of success; they seem to tolerate at least moderately alkaline conditions, but neutral to slightly acidic soil is probably preferable. Seedlings are easy to raise in moist, humid conditions but the species are prone to hybridise, so selected clones should be propagated by semi-ripe cuttings in late summer.
