Callistemon sieberi

River Bottlebrush

Family: Myrtaceae

Callistemon sieberi is a shrub or tree growing to 8 m tall, with fibrous bark, or hard, fissured bark on older plants.

It is naturally widespread along watercourses, dried and rocky riverbeds and gullies on the coast, tablelands and western slopes and plains of NSW.

It occurs from Warwick in the far south east of Queensland, through New South Wales as far inland as the eastern part of the North West Plains to the eastern half of Victoria.

Callistemon spp. have simple and alternate leaves, often arranged in a spiral. In this species, leaves are arranged alternately and are about 7 cm long, up to just less than 1 cm wide, linear to narrow-lanceolate and have a small point at the end.

In Callistemon species, flowers are usually arranged in spikes (the “bottlebrush”) which are produced at the terminals but which the stem then grows past, into a leafy shoot. Flowers have five small circular sepals and five circular petals which persist on the flowers.
Like many other Myrtaceae genera, the flowers are conspicuously staminate with each flower having many stamens surrounding one carpel. The stamens are typically free although may be fused at the basal parts (a generally useful identifying feature for the genus to distinguish it from Melaleuca). The pedicels of the flowers are very short. In this species, the flowers are a shade of cream to yellow, occasionally pink, in spikes on the ends and sides of branches which continue to grow after flowering. The spikes are to 5 cm long and 3 cm wide with up 40 individual flowers, each about 5 to 10 mm wide. Flowering occurs mainly from October to January

The fruit is a woody capsule. In this species, they are cup-shaped, to 4 mm long and arranged on the same flowering structure.

In the garden

Attractive to birds and insects.

The plant responds to annual fertilising after flowering and may be pruned severely if necessary. Prune 2/3rds off spent flower to encourage prolific growth and reduce woody stems.

Is a hardy plant that can be used as a hedge.


Propagation is easy from both seed and cuttings

Other information

The genus Callistemon has been subject to recent taxonomic revision with early and recent botanists including Ferdinand von Mueller and Lyndley Craven (deceased in 2014) proposing to ‘lump’ the genus into Melaleuca and others. Craven et al. (2014) published new species combinations which included the renaming of all Callistemon species to Melaleuca, based on evolutionary relationships and DNA evidence and other features.

Currently, the NSW Herbarium advises that the Callistemon genus can still be used. There are currently about 30 species of Callistemon, which are found in all states of Australia as well as New Caledonia. About 28 are endemic to Australia. NSW currently recognises 24 species. New species have been described in the last 20 years.

Can regenerate from seed as well as reshooting stem buds and coppicing after fire.

Callistemon – From the Ancient Greek – Kallos (κάλλος) – meaning “beautiful” (which is changed to κάλλη to describe a noun) and stêma (στῆμα) meaning “stamen”, referring to the very showy staminate flowers of the bottle-brush inflorescences.

sieberi – named in Honour of Franz Sieber (1789-1844), a botanist from the Czech Republic who spent 7 months in Sydney collecting over 600 plant specimens in 1823.

This species is not considered to be at risk of extinction in the wild.

NSW Flora Online (PlantNET) – Callistemon sieberi profile page

Australian National Herbarium – Calllistemon sieberi profile page          https://www.anbg.gov.au/gnp/trainees-2018/callistemon-sieberi.html

Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.


By Jeff Howes. Editing and additional text by Dan Clarke.