General Description:

Calochilus is a genus of about 30 species which mostly occur in Australia but some are also found in New Caledonia, New Guinea and New Zealand.

Calochilus robertsonii is a perennial herb, having a single, narrow leaf 150 to about 400 mm high and 4 to 8 mm wide. Several reddish-brown flowers occur on a thin stem during spring and sometimes extend into summer.  They are usually about 25 mm long and up to 8 mm wide and have a distinctive bearded labellum.  Plants become dormant in summer when they die back to an underground tuber.

Most Australian terrestrial orchids require specialised cultural needs and are cultivated mainly by orchid enthusiasts. Generally the plants are grown in pots in a freely draining, sandy mix. They require good air circulation in a protected position of about 50% sun during the growing period from autumn to spring. During this growing period the plants must not be allowed to dry out. After the leaves have turned brown in late spring to early summer the pots are allowed to dry out completely. Repotting of tubers can be carried out in summer. Calochilus robertsonii has been successfully cultivated to flowering but has proved to be difficult to maintain for an extended period.

For further information on terrestrial orchid cultivation see Australia’s Native Orchids by Les Nesbitt.

Propagation of orchids requires specialised methods and is rarely attempted by the casual grower. The following references provide further information on growing terrestrial orchids from seed.

• Australian Terrestrial Orchids from Seed; D K McIntyre, G J Veitch and J W Wrigley
• A New Medium for Raising Australian Terrestrial Orchids from Seed; G J Veitch and D K McIntyre

Both articles appear in Australian Plants, journal of the Australian Native Plants Society (Australia), March 1973.