Eucalyptus siderophloia

Northern Grey Ironbark

Family: Myrtaceae

A tree, growing to a height of 20 to 45 m, forming a lignotuber, with ironbark.

It has a mainly coastal distribution in NSW, growing north of Sydney, through the Hunter Valley and coastal interior, into Queensland where it extends to around Bundaberg and Lowmead as well as Carnarvon National Park. 

It is found in forests on the coast and adjacent foothills in soils of reasonable fertility.

Bark is hard, rough, furrowed grey or black on the trunk and branches (ironbark), sometimes smooth on the thinner branches.

Eucalyptus spp. have simple and usually alternate adult leaves with juvenile leaves starting off opposite to alternate (disjunct). In this species, juvenile/coppicing leaves have ovate to lanceolate leaves that are paler on the lower surface, to 120 mm long and to about 50 mm wide.
Adult leaves are the same shade of green on both sides, lanceolate to falcate, to 175 mm long and to 30 mm wide, tapering to a petiole to 25 mm long.

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 flowers are mostly arranged on the ends of branchlets in umbellasters of seven. Mature buds are diamond-shaped or spindle-shaped to 10 mm long and to 4 mm wide with a conical operculum / calyptra. Flowering mainly occurs from September to January and the flowers are white.

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 or conical, to 8 mm long and to 7 mm wide with the valves near rim-level.

In the garden

In a garden situation, it is fast-growing and hardy, and adapts to most well-drained sites. Tolerates some frost. It is not overly common in cultivation but could be planted in an open garden or as a street tree. It has very dramatic black bark which contrasts with the green leaves. Not recommended for small gardens. Lends to larger landscapes and gardens. Suitable for dry climate gardens. Frost tolerant.

A Koala food tree. This species is one of 27 more common Eucalypt and Corymbia plants eaten by them.
Eucalypts can suffer problems from, caterpillars, leaf eating beetles, psyllids and borers to name a few. In undisturbed conditions, the numbers of eucalypt-feeding insects and their predators and parasites are in balance, so that they rarely cause tree death and most trees quickly recover from attack. In a home situation nature can get out of balance.


Eucalypts 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

Regenerates from lignotuber after fire and epicormic growth. Wil also regenerate from seed.

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).

siderophloia – is derived from Greek, sidero (σίδερο) – meaning “iron” and phloios (φλοιός) – “bark” – referring to the iron-bark of the species.

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

Field Guide to Eucalypts – Vol 1 South Eastern Australia M.I.H.Brooker and D.A.Kleinig. Blooming Books.

NSW Flora Online (PlantNET) – Eucalyptus siderophloia profile page

EUCLID – Eucalypts of Australia – Centre for Australian National Biodiversity Research – Eucalyptus siderophloia profile page            https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_siderophloia.htm

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