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.
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