In 1983, Ron Robjohns, NOSSA’s first treasurer, wrote a comprehensive series of articles about growing epiphytes in South Australia. Thirty years on Ron’s information for growing is still helpful and applicable for today. Any updates or extra information are in black text.
NATIVE ORCHID SOCIETY OF SOUTH AUSTRALIA JOURNAL
Volume 7, No. 9, October, 1983
GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns
Dendrobium aemulum (Iron Bark Orchid)
There are several growth forms of this orchid due probably to the wide variety of habitats, the flowers of all forms being similar. It has a range from the Clyde River in south eastern New South Wales to the Atherton Tablelands in Queensland
Those growing in the rainforests of New South Wales and Queensland have straight stems up to 20 cm long with 2-4 shining dark green leaves. On the edge of the rainforests in northern New South Wales and southern Queensland in the dense brush forest, the principal hosts are the trunks of “Brush Box” trees where it has stems up to 30 cm long which tend to radiate from a central point. It also has 2-4 dark green leaves. In the open forest areas its hosts are the “Iron Bark” eucalyptus trees, it has shorter (up to 7 cm), stouter (up to) 1 cm), and more crowded stems, sometimes growing into large mats and having 2-4 yellowish green leaves. On the Atherton Tablelands at an altitude of around 750 metres and with callitris trees as its favoured host, it has very slender stems of about 0.3 cm with usually only two dark green leaves.
The flowering period is August/September. One to three slender racemes (5-10 cm long) occur terminally from between the leaves or at nodes along the stem, each raceme bearing 3-20 cm diameter. The flowers are usually pure white (sometimes pale cream) with purple markings on the labellum, the whole raceme turning deep pink before withering.
This is another of our natives which to date does not appear to have attracted much attention from the hybridisers. “Emmy” aemulum x kingianum seems to be the only registered cross.
I find D. aemulum is an easily cultivated and highly rewarding plant that flowers freely with masses of feathery flowers. It grows well mounted on hardwood slabs, cork or on a paperbark branch under 50% shadecloth. Mine get about 65% shade in mid-summer and receive an occasional spray of weak foliar fertiliser during the growing period.
Reference: Dockerill “Australian Indigenous Orchids”.