Cyathea australis

Rough Tree Fern

Family: Cyatheaceae

C. australis is an arboreal tree-fern growing to potentially 20 m tall. It is known as the Rough Tree Fern due to the presence of shield-like plates (bases of old fronds), tubercles (knobbly bits) and masses of hair-like scales on its ‘trunk’.

It is found typically in rainforest as well as wet sclerophyll forest all along the NSW coast and tablelands, and into the western slopes. It also grows in Qld, Victoria and Tasmania. It prefers moist mountain areas and can grow on dryer slopes compared to most other tree ferns.

The radiating fronds are finely divided and may be up to 4.5 metres long.

Spores are produced on underside of fronds.

In the garden

A popular, cold-hardy tree-fern, adaptable to a variety of climates and soils. A great background or feature plant that is an extremely hardy.

They are even capable of tolerating direct sun when the roots are kept wet. Responds well to fertiliser.

Given the right conditions they can grow 50 cm a year.

Plants grown in full sun can have their fronds burnt in very hot days.

Propagation

From spores.

Large tree ferns are often sold by nurseries as trunks sawn off at the base. These are Dicksonia antarctica and they quickly form roots from the base when planted. Cyathea australis cannot be treated in the same way and will not grow from sawn off sections and cannot be reliably transplanted.

Other information

Regenerates from spores after fire. Possibly old plants can reshoot if burnt.

Cyathea – from the Ancient Greek ‘kyatheion’ (meaning small cup, referring to the compartment within the overall structure (sorus) that holds the spores.
australis – means southern, or ‘of the southern hemisphere’.

https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Cyathea~australis
https://vicflora.rbg.vic.gov.au/flora/taxon/452c3d6a-a68b-47c1-9b88-f08060ab752b

By Jeff Howes