Cyathea Australis Descriptive Essay

Cyathea australis is a superb looking Tree Fern from the forests of Southeast Australia (and Tasmania and Norfolk Island) comes this medium to large sized tree fern. In the wild it inhabits moist mountain areas in Victoria, New South Wales, and Queensland, and is often found growing in the company of Dicksonia antarctica but preferring more sunny open spots.

It has a large, very rough, woody trunk with long weeping dark green fronds that are pale green underneath. Trunk sizes have been found to grow up to as high as 20 metres! It’s common name, the Rough Tree Fern, comes from the extremely rough texture of the remaining stipe bases on the trunk.
This name is well founded as I can testify have grappled with them when planting and emptying containers!

This characteristic of the trunk gives this hardy tree fern a very striking appearance in comparision to Dicksonia antarctica.

Cyathea australis is adaptable to a variety of soil types and make an ideal garden or tub plant. As with most Tree Ferns it likes plenty of water but tolerates considerable exposure to direct sunlight and is more resistant to strong wind than Dicksonia antarctica.

In Australia it grows in more exposed sites than Dicksonia antarctica and is potentially as hardy although developing fronds appear somewhat more sensitive to frost. In the colder parts of Ireland winter protection of the trunk is recommended and as with all Tree Ferns the crown should be filled with straw, leaves or as in my case pine needles.

This is a big favourite of mine and is highly recommended for those who want to add a new Tree Fern species to their collection. I have absolutely no problem with this plant. The new croziers are a delight to watch unfurl around April to May time.

Hardiness: : Hardy to no more than -8 Celsius (for short periods)

Cyathea australis


Cyathea australis


Cyathea cooperi stem

     Rough Tree Fern

Cyathea cooperi

     Lacy Tree Fern

Cyathea australis (R.Br.) Domin
Cyathea cooperi (Hook. ex F.Muell.) Domin

Tree-ferns are the largest of the ferns and can provide a spectacular addition to most gardens. The tree-ferns Cyathea australis and Cyathea cooperi are commonly grown in gardens and displays for this aesthetic appeal and their hardiness. Both of these species are of the fern family Cyatheaceae.

C. australis is commonly known as the Rough Tree Fern due to the presence of adventitious roots, tubercles (knobbly bits) and masses of hair-like scales on its ‘trunk’. The ‘trunk’ like structure on a tree-fern is actually a greatly enlarged rhizome! The horticultural appeal of C.australis is not only due to its beautiful looks but also because it is an extremely hardy species, even capable of tolerating direct sun when the roots are wet. It is also a robust tub plant and is unusual in that it is tolerant of salty winds. C. australis is thus a popular, cold-hardy tree-fern, adaptable to a variety of climates and soils.

C. cooperi, the Lacy Tree Fern, derives this name from its delicate fronds. It is also known as the Australian Tree Fern as it is one of the most commonly grown Australian tree-ferns.

C. cooperi is quite distinctive from C. australis in that it has a more slender trunk with distinctive "coin spots" where old fronds have broken off the trunk. C. cooperi fronds are bright green and lacy and tend to be very fast growing. There are several major horticultural varieties of this fern including Cyathea ‘Brentwood’ which has paler fronds and scales and C. ‘Robusta’ which tends to be darker in both characters. C. cooperi is the one of the most popular tree ferns, along with Dicksonia antarctica due to its rapid growth form, hardiness and aesthetic appeal.

Distribution:

C. australis is found along much of the east coast of Australia, extending right down into Tasmania. It prefers moist mountain areas and can grow on dryer slopes then most other tree ferns.

C.cooperi is naturally found in tropical lowlands, along the coast of Queensland and New South Wales.

Propagation:

These two species cannot be propagated vegetatively (unlike some other tree-ferns) as they do not produce offsets from the trunk or roots. Propagation from spores must therefore be employed; for detail of these steps please see this page: http://www.anbg.gov.au/ferns/fern.spore.prop.html

Maintenance

Tree-ferns grow best in high humidity and high soil moisture conditions. It is therefore important to use good-quality mulches and to top them up regularly as this will not only keep the soil moist but also provide nutrients to the shallow root system. Tree-ferns usually respond well to organic fertilizers and well-rotted animal manures, C. cooperi especially as it tends to display particularly vigorous growth.

Though a wide range of pests attack ferns they rarely cause significant damage. If outbreaks do occur tree-ferns can be treated with the standard array of organic and non-organic pesticides. It has been found that the use of fertilizers can reduce a tree-ferns susceptibility to attack. Thus by providing adequate food, water and shelter you will be able to grow beautiful and healthy tree-ferns in your own garden!

Text by Ali Heydon (Botanical Intern 2003)

Derivation of the names:

Cyathea - from the Greek 'kyatheion' meaning little cup, referring to the structure that holds the spores.

australis - means southern, or 'of the southern hemisphere'.

cooperi - named by Ferdinand von Mueller in honour of Sir Daniel Cooper (1821-1902). Cooper was a Member of the old New South Wales Legislative Council from 1849 and of the new Legislative Assembly after responsible self-government was granted in1856. He was elected the first Speaker of the Legislative Assembly and held that office until his resignation in1860.

 

References

Jones, D.L. 1987, Encyclopaedia of Ferns, Lothian, Melbourne.

Jones, D.L. Clemesha, S.C. 1980, Australian Ferns and Fern Allies, Reed, Wellington.

Harvey, R. Fagg, M. Growing ferns from spores, Australian National Botanic Gardens leaflet published online at:
http://www.anbg.gov.au/ferns/fern.spore.prop.html
Updated 18 July, 2002.

Ian Barclay, Cold Hardy Tree Ferns, Published Online at:
http://www.angelfire.com/bc/eucalyptus/treeferns/
Last updated: December 8th, 2002.

 

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