One of the first Australian plant species to be grown in European gardens was the bottlebrush. Callistemon citrinus, crimson bottlebrush, was seen and collected by naturalists Joseph Banks and Daniel Solander in 1770 at Botany Bay, New South Wales. The plant was introduced into Kew Gardens and Sion House. By the 1790s it was readily available from London nurseries. Callistemon viminalis, weeping bottlebrush, seen at Endeavour River was also collected. There are now many other cultivated species, including several cultivars.
The genus Callistemon is closely related to the genus Melaleuca, the so-called paperbarks. The name Callistemon, first used by Robert Brown in 1814, is derived from the Greek ‘calli’ meaning beautiful and ‘stemon’ meaning thread or stamen. This genus, consisting of evergreen shrubs, is endemic to eastern and south eastern Australia, including two species from Western Australia and two others from Tasmania. Both the crimson and weeping bottlebrushes have attractive red inflorescences comprising dense cylindrical spikes of flowers. The colour is produced by the masses of stamens in each individual flower, not from the petals. The stamens are arranged on top of the floral tube. In Callistemon the stamens are free from each other, while in Melaleuca species they are united into five groups. Very small, cream-coloured petals are inserted at the base of the stamens around the floral tube. In some species the stamens are yellow, white or pink. The axis of the inflorescence continues growing beyond the head of the flowers to produce new leaves. Clusters of seed capsules remain surrounding the stems on previous year’s growth. Abundant nectar is produced by the flowers, providing food resources for bees and nectar-feeding birds.
Besides use its use in horticulture, essential oils found in the leaves of Callistemon species have been recognised as having antioxidant, antifungal and antibacterial properties. These potential uses are being investigated. A dye can be obtained from the flowers of Callistemon citrinus. Callistemon viminalis has been used to control soil erosion along waterways and to slow the flow of floodwater.
Recent taxonomic revision has suggested that Callistemon species should be re-classified within the genus Melaleuca, although this conclusion has yet to be accepted universally. Independent of the genus to which they belong, bottlebrushes make excellent cultivated plants. They flower best in sunny positions, being tolerant of various soil types, are mostly frost hardy, can bounce back after heavy pruning and are easy to propagate from cuttings.
Craven LA 2006. New combinations in Melaleuca for Australian species of Callistemon (Myrtaceae). Novon 16: 468-475.
Wrigley JW and Fagg M 1993. Bottlebrushes, paperbarks and tea trees. Angus & Robertson.