Cyatheaceae
Common Name: Tree Fern

There are over 600 species in this genus of handsome tree ferns, found growing naturally in cool, moist gullies in tropical and subtropical regions around the world. Some species are native to cool montane regions with frequent fog or mist and semi-permanent cloud cover. Others occur naturally in warmer regions, but often at high altitude. The trunk varies from thick to slender, depending on the species, but is always erect. The large fronds spread and curve, and are variably divided. They all bear scales, but of varying types. The fertile fronds have round spore cases, along the leaflets on either side of the mid-veins. Stems of these tree ferns bear the scars of old fronds.

Species

C. australis, rough tree fern, has a narrow, tall, rough trunk, which turns black with age. Both the trunk and the stems are covered in shiny brown scales. The large, light green fronds become darker when exposed to increased sunlight. When planting or transplanting this species, the roots must be kept intact. The hole into which the tree fern is to be planted should be reasonably large and the soil enriched with leaf mould. It can tolerate sun, provided its roots are kept moist.

C. cooperi, Cooper's tree fern, from north-east and eastern areas of Australia, has a large trunk, which frequently reaches 9 m (30 ft) in maturity, with oval scars from the old stems. The fronds are large and quick growing and the stems are covered in cream scales, edged with reddish brown 'thorns'.

C. cunninghamii, slender tree fern, is found growing naturally in the cooler southern parts of Australia. It has a slender trunk, to 6 m (20 ft), fine, tall, scaly stems, and upward-curving leaflets. This soft tree fern needs protection from frost, wind and intense sun, but will do well in cool, moist gullies.

C. dealbata, ponga or silver fern, is New Zealand's national emblem. The trunk, to 10 m (33 ft) tall, bears a mass of spreading fronds, coloured silver-gray on the undersides. The fine stems are covered in long, brown, shiny scales. This handsome species can produce offshoots from the base.

C. medullaris, mamakee or black tree fern, from New Zealand, is a tall species, which reaches 10 m (33 ft). The trunk is narked with the characteristic scar pattern and the fronds are large and spreading.

Cultivation

In areas prone to frost, grow in a cool to warm greenhouse or conservatory. They will need a large pot or tub containing soil-based compost with added leaf mould. They need good light but shade from direct sun, and a humid atmosphere. Spray trunk and foliage with plain water in growing season. Outside, these ferns are cultivated in a similar way to other tree ferns, but individual species may have specific requirements. Generally, they like a mild to warm climate, plenty of moisture, and protection from hot sun and strong wind. Propagate from spores.

Climate

Zone 9, provided it is relatively frost-free.