Cyathea australis

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Plant
ID 433 Cyathea australis
Botanic Name Cyathea australis
Common Name Rough Tree Fern, Australia Tree fern
Family Name Cyatheaceae
Cultivars syn. Alsophila australis
Origin Australia, Norfolk Island, Zone 9-11
Growth Type Fern
Bark Type Leaf scars or bases
Foliage Type Evergreen Water Use Low
No. of Species 800
Growth Habit Standard Growth Rate Medium
Height 7 - 12 m (23 - 40 ft) Spread 3 m (10 ft)
Plant Overview
This tall tree fern has an erect slender trunk (caudex) up to 300 mm (12 in) in diameter with a buttress base and is covered with scales. It has arching divided mid green fronds up to 4 m (12 ft) long that spread from the crown in a umbrella-like fashion.
Leaf
Type Compound Additional Information
Shape Bipinnate
The arching bipinnate fronds are up to 3.5 m (11 ½ ft) long and are dull green above and glaucous below with the leaf segments divided 2 to 3 times (tripinnatifid). The apex is acuminate and the long petiole is covered in brown scales.
Arrangement Rosette
Margin Entire
Colour Mid green
Size 1500 - 3500 mm ( 59.1 - 137.8 in )
Flower
Perfume Additional Information
Shape
The cup-shaped sori appear as a raised cluster on either side of the mid rib on the underside of fertile fronds. They have no indusium and appear during summer.
Inflorescence Sori
Colour Brown
Size 0 - 0 mm ( 0.0 - 0.0 in )
Flowering in
(Southern Hemisphere)
Jan Feb Mar Apr May Jun
Jul Aug Sep Oct Nov Dec
Fruit
Type Sporangium Additional Information
Colour Brown
The spores are produced in the sporangium during the sporophyte stage of the fern life cycle in rows either side of the mid rib on the underside of fertile fronds. The spores are very small (like fine dust) and are released from the sori when mature.
Edible No
Bird Attractive No
Size 0 - 0 mm ( 0.0 - 0.0 in )
Fruiting in
(Southern Hemisphere)
Jan Feb Mar Apr May Jun
Jul Aug Sep Oct Nov Dec
Environment & Cultivation
Natural Soil Well drained sandy-clay loam, organic rich, moist, acidic, pH 6.0-7.0
Container Pots, tubs, large planter boxs, warm greenhouse in frost prone climates
Climate Warm to sub-tropical
Aspect Semi-shade to full sun, frost and drought tender, moist protected position
Pest & Diseases Sun, wind and frost burn, passion vine hopper, re-shoots after fire
Fertiliser Keep moist, regular light application of liquid fertiliser, mulch with composted material
Pruning Remove spent fronds, litter problem; falling spores and fibers
Cultural Uses Propagation
The Rough Tree Fern is vigorous and is grown for its upright habit. It is planted in parks or gardens as a specimen or in group plantings in gullies for a tropical effect. It is also grow in tubs and planter boxes or used around a water feature.
Place spores on sterilised sphagnum moss or peat moss and cover with glass. Keep them warm and moist and in 4 to 6 weeks the prothallus appears. It is easily transplanted when mature during spring, just reduce foliage and keep moist.
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