Eucalyptus smithii

Ironbark Peppermint, Gully Gum, Gully Peppermint, Blackbutt Peppermint

Family: Myrtaceae

A large tree usually (but also found as a mallee), forming a lignotuber, growing to a height of 40–45 m. It is typically found in higher rainfall areas, on sloping sites, on the coast and tablelands of NSW, south from Yerranderie, to eastern Victoria. It is a common tree in areas such as the southern highlands of NSW.

It typically has a straight upright trunk with a narrow-leaved canopy. It can be found on sandstone soils as well as enriched sandy soils and basalt.

The basal bark is rough, fibrous, compact and dark grey-brown to black bark on the trunk, resembling ironbark in some cases.

The upper bark on the branches (and on the trunk and branches of mallees) is smooth and white to cream-coloured. Upper branch bark is shed in long ribbons.

These combined features are a useful identification feature.

The leaves of young plants to early sapling stage are arranged in opposite pairs, green to greyish, narrow lance-shaped or cordate, to 110 mm long and to 25 mm wide, with their bases clasping the stem.

Adult leaves are arranged alternately, the same shade of slightly glossy green on both sides, narrow lance-shaped to curved, to 210 mm long and to 16 mm wide, with the base tapering to a petiole to 28 mm long.

The flower buds are arranged in leaf axils in groups of seven. Mature buds are oval to diamond-shaped to 6 mm long and to 4 mm wide with a conical to beaked operculum / calyptra. Flowering occurs from December to January and the flowers are white.

The capsules are cup-shaped, bell-shaped or hemispherical to 6 mm long and 4 to 8 mm wide with valves strongly protruding above the rim. The top of the capsule has a distinctive somewhat-trapezoidal shape with 3 valves – a useful feature in identification.
Seeds black, brown or grey, about 3 mm long, ovoid or flattened-ovoid, often pointed at one end.

In the garden

Not overly common in gardens and cultivation but they can be observed growing in lawns and gardens surrounding houses in areas such as the southern highlands of NSW. They can grow to be very large so not suited to small gardens. Very useful and attractive in large gully landscapes or even close to hill tops, as well as along creeklines. They can be very grandiose when large.

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.

Propagation

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.

Other information

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

Is widely grown in southern Africa, and its leaves are used for the production of distilled eucalyptus oil. The oil is high in cineole (75–84%).

Regenerates from fire from epicormic shoots and lignotuber.

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).

smithii – honours academic chemist Henry George Smith (1852 – 1924), for his pioneering work on essential oils of eucalypts and other Australian flora. His work on the essential oils of the Australian Flora achieved world-wide recognition.

Not considered at risk in the wild.

“Field Guide to Eucalypts Vol 1 South Eastern Australia’ M.I.H.Brooker and D.A.Kleinig. Blooming Books.
https://en.wikipedia.org/wiki/Eucalyptus_smithii
https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_smithii.htm
https://en.wikipedia.org/wiki/Eucalyptus
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~smithii

By Jeff Howes, edited Dan Clarke