Eucalyptus robusta

Swamp Mahogany, Swamp Messmate

Family: Myrtaceae

A tree to 30 m tall and occurs in swamps and alongside estuaries in a narrow coastal strip, usually within a few kilometres of the ocean, from Rockhampton, Queensland, south to around Moruya in New South Wales. It is usually found on sandy and loam soils. It forms a dominant part of Swamp Sclerophyll Forests in NSW.

Bark covers the trunk and branches and is stringy to tessellated, thick red-brown in colour and has a spongy feel. The long branches spread laterally and form a dense canopy with the broad green leaves which are arranged alternately along the stems.
These leaves are to 16 centimetres long and to 4.5 cm wide, broadly lanceolate to ovate, green and glossy, and with closely spaced “feather-like” side veins running at greater than 45° angle to the main midrib.

Flowers are white or cream-coloured and clustered in inflorescences (umbellasters) of 7 to 13 flowers. The flowers appear anywhere from March to September, and peak over May and June. The buds measure 2 by 0.8 cm wide and are distinctive in that the operculum / calyptra has a prominent long beak, making them spindle-shaped (useful feature in identification).

The capsules are cylindrical-shaped and very different to any other eucalypt it grows with, to 1.6 cm long to about 1 cm wide (useful feature in identification).

Seeds are light-brown to yellow to 1.8 mm long, pyramidal or obliquely pyramidal in shape.

In the garden

E. robusta adapts well to cultivation, though it often grows too large for home gardens. It can grow very quickly in cultivation and flower profusely.

It will tolerate wet and swampy conditions. It prefers a sandy soil. Will do well in an open area for a shade tree or specimen planting.
A row of E. robusta was planted at the Royal Botanic Gardens, Sydney in 1813, and the trees are still healthy today.

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.

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. 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.
Refer to these two links for more clarification:
http://anpsa.org.au/eucal1a.html
http://anpsa.org.au/APOL2/jun96-5.html

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).
robusta – Latin robustus, robust / strong / firm, referring to the appearance of the trees generally and canopy.

“Field Guide to Eucalypts Vol 1 South Eastern Australia’ M.I.H.Brooker and D.A.Kleining. Blooming Books.
https://en.wikipedia.org/wiki/Eucalyptus_robusta
https://en.wikipedia.org/wiki/Eucalyptus
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~robusta

By Jeff Howes