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Rough Tree Fern

Cyathea australis

Family: Cyatheaceae
Genus: Cyathea (sigh-ATH-ee-uh) (Info)
Species: australis (aw-STRAL-iss) (Info)
Synonym:Alsophila australis



Foliage Color:

Unknown - Tell us

Bloom Characteristics:

Unknown - Tell us

Water Requirements:

Unknown - Tell us

Where to Grow:

Unknown - Tell us


10-12 ft. (3-3.6 m)

12-15 ft. (3.6-4.7 m)

15-20 ft. (4.7-6 m)

20-30 ft. (6-9 m)

30-40 ft. (9-12 m)

over 40 ft. (12 m)


12-15 ft. (3.6-4.7 m)


USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Sun Exposure:

Partial to Full Shade



Bloom Color:


Bloom Time:



Grown for foliage

Other details:

This plant may be considered a protected species; check before digging or gathering seeds

Soil pH requirements:

Unknown - Tell us

Patent Information:


Propagation Methods:

From spores

Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed


This plant has been said to grow in the following regions:

Hayward, California

Miami, Florida

Naples, Florida

Gardeners' Notes:


On Dec 20, 2015, WalkingStick from Olympia, WA wrote:

I started spores of this tree fern in March of 2015 and as Dec 2015 have four small 2" ferns growing indoors with the intent of growing them on my balcony. I could have had many more, but even four, if they do well, will be more than enough. I put the remaining prothallus plus one just starting to develop into a recognizable fern outdoors, and, to my surprise have survived light frosts.

This is the first time I have intentionally grown ferns from spores. Living in the damp cool Pacific Northwest of the US, we have many native ferns that spontaneously grow in abundance in the ground or in pots.


On Jul 12, 2007, Cretaceous from El Sobrante, CA (Zone 9b) wrote:

Cyathea australis is native to Australia (Queensland, New South Wales, and Tasmania). This species is tolerant of wet or poorly drained soils.

The subspecies norfolkensis is endemic to Norfolk Island:

Cyathea are listed on CITES Appendix II.


On Sep 10, 2003, kennedyh from Churchill, Victoria,
Australia (Zone 10a) wrote:

This tree fern is the commonest species in southern Australia, growing in large numbers in wet schlerophyll forest and rainforest. It is usually about 3 metres tall, but can grow as high as 15 metres. The name Rough Tree Fern relates to the trunk, which is rough because it is covered with the bases of all the old fronds. It also contrasts it with the Soft Tree Fern - Dicksonia antarctica, which grows with it.

The Soft Tree Fern has a smooth fibrous trunk with no remnants of the old fronds. It is nowhere near as common in cultivation as the Soft Tree Fern, because it does not transplant easily and is very slow growing from spores.