Eucalyptus fracta

Broken Back Ironbark

Family: Myrtaceae

A small tree, to around 8 metres, or a mallee. It has grey-black ironbark on its trunk and larger branches with smooth whitish bark on smaller branches. Mature trees show the typical ironbark trunks, while the smaller, upper branches are smooth and whitish.

It is endemic to the Hunter Valley in NSW, found primarily along the Broken Back Range near Pokolbin, with scattered populations along the southern escarpment of the valley. It is found growing along the edges of the escarpment. Plants closer to the edge of cliffs tend to grow more as a mallee, with those further from the edge growing as trees. 

It grows mainly in sandy dry sclerophyll woodland to shrubland.

It is a listed threatened species in the wild.

Eucalyptus spp. have simple and usually alternate adult leaves with juvenile leaves starting off opposite to alternate (disjunct). In this species, juvenile leaves are round and blue green in colour. Adult leaves more spear-shaped to lanceolate, to 11 cm long and 2.5 cm wide, grey-green and glossy.

The primary inflorescence of “eucalypts” (Angophora / Corymbia / Eucalyptus) is an umbellaster (an umbel-like cluster of flowers). In the flowers of Corymbia and Eucalyptus, the petals and sepals are fused into the distinctive calyptra / operculum (bud cap) which is shed when the flower opens (in some species, 2 bud caps (opercula) are shed). The flowers are conspicuously staminate – where many stamens are basically taking over the role of the petals, all surrounding one central carpel. In this species, the flower buds are clustered in umbellasters of 7, which are arranged in secondary groups in leaf axils, which mature to white flowers in spring. 

The fruit of eucalypts are a woody capsule (commonly called ‘gum nuts’) which come in a wide variety of shapes with the top part having a sunken, flat or raised disc and with the valves inserted, disc-level, exserted to strongly exserted. In this species, the capsule is cup-shaped, to 8 mm long and 7 mm wide. 

In the garden

Not yet in cultivation. This is likely due to its listed threatened status. It may be available for cultivation in the future. 


Eucalyptus can be propagated by seeds which is most common method or grafting.

Cuttings are difficult to start, but can be used in some species. For further information refer to: http://anpsa.org.au/APOL2007/sep07-s1.html

Other information

Eucalyptus is one of three similar genera that are commonly referred to as “eucalypts”, the others being Corymbia and Angophora.

Regenerates from lignotuber and epicormic growth after fire.

Eucalyptus is one of three similar genera that are commonly referred to as “eucalypts”, the others being Corymbia and Angophora. It is well-known that Eucalyptus is a large and diverse genus. Between 700 and 950 known species are reported, occurring as far north as The Philippines, as well as Indonesia, New Guinea, Timor and Australia. Only 16 species reportedly occur outside Australia. They occur in all Australian states. NSW currently has about 250 species. (See this website for some detailed information: https://apps.lucidcentral.org/euclid/text/intro/learn.htm).

Eucalyptus from Greek, eu, “well” or “true” and calyptus, referring to the calyptra (καλύπτρo) or operculum, which is a bud cap or covering which covers the developing flowers. The calyptra is a fusion of petals and/or sepals and is shed when the flower opens, leaving a flower with many stamens (staminate) surrounding one female part (carpel).

fracta – Latin meaning ‘broken’ which refers to the separated nature of the populations of the species. It was first named in 1997 by Ken Hill, from a specimen found in Charmhaven with Leonie Stanberg in 1995.

This species is listed as threatened with extinction at the State level with the category of Vulnerable. 

NSW Office of Environment Threatened Species Profile – Eucalyptus fracta https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10294

Wikipedia – Eucalyptus fracta profile page                            https://en.wikipedia.org/wiki/Eucalyptus_fracta

NSW Flora Online (PlantNET) – Eucalyptus fracta profile page            https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~fracta  

By Mark Abell. Editing and additional text by Dan Clarke