Gardening Australia – September 2019

PLANTS

26 SEPTEMBER 2019 GARDENING AUSTRALIA

trunks among tree ferns. Found naturally
in forests from south-east Queensland to
Tasmania, this species can grow 12–15m
tall, but is more likely to mature at 4–5m.
The graceful arching fronds produced in
spring and autumn can extend 3–4m long.
The stalks are smooth and covered in fi ne,
reddish-brown hairs, while the leaves are
dark green above and lighter underneath.
A shorter version is the golden tree fern
(D. fi brosa), which is similar but reaches
a height of only 4–6m at most. Its fronds
are shorter, too, and golden in appearance.
Dead fronds are held on the plant, creating
an unusual ‘skirted’ trunk. Indigenous to
extremely cold areas of New Zealand, it
also tolerates sun in cool climates.
Another New Zealand native is wheki
(D. squarrosa), also known as the rough
tree fern or harsh tree fern. It is much
faster-growing than its Australian relative,
potentially putting on 10–80cm of trunk a
year, albeit with fewer and shorter fronds,

and can reach up to 6mtall.Itspreadsvia

rhizomes and can formcoloniesoftrunks.

It is somewhat wind tolerantandwillgrow

in full sun if the roots arekeptmoist.

Cyathea species

Growing to 20m in thewild,anotherrough

tree fern (Cyathea australis) is one of the

tallest tree ferns. Occurring in forests from

south-east Queensland to Tasmania, it is

named for the knobbly bits on its trunk and

the short, coarse, densely packed spines

at the base of the stems (stipes). It’s a

fast-growing species with fronds that

grow 2–5m, creating lovely fi ltered shade

below. Rough tree fern is a popular choice

for gardens because it can withstand the

sun if its roots remain moist, and it will

tolerate salty winds in coastal gardens.

Lacy tree fern (C. cooperi) is so-named

for its largely divided ‘lacy’ fronds. These

reach up to 5m long on a 15cm-diameter

trunk that grows up to 12m tall, giving the

plantanelegant,palm-likeappearance.

It also has distinctive coin-like spots left

where old fronds have broken away from

the trunk. Found in forests from Far North

Queensland to south-east coastal New

South Wales and south-west Western

Australia, it prefers warmer, frost-free

areas, where it grows quickly.

With its characteristic slim black trunk

reaching 20m tall, and 5m-long arching

fronds with black stipes, the black tree

fern (C. medullaris) is much sought after.

Hailing from New Zealand, Fiji, Tahiti

and other Pacifi c islands, it may take a bit

of hunting down. It is fast-growing and

cold-hardy and copes with wind andsun

exposure if the roots are kept moist. GA

SUSTAINABLE

SOURCES

Dicksonia antarctica and

Cyathea australis require

a permit to harvest from the

wild and are sold with a

licence number. Source tree

ferns from a reputable

nursery, to reduce illegal

and unsustainable

harvesting.

CLOCKWISE FROM LEFT

Soft tree fern (Dicksonia antarctica) has one

of the widest trunks among tree ferns; harsh

tree fern (D. squarrosa) spreads by rhizomes,

with multiple plants forming a lovely shady

arbor; a golden tree fern (D.  b r o s a) with

a new  ush of distinctive ‘gold’ fronds.

PHOTOS

GAP PHOTOS/NICOLA STOCKEN, ISTOCK, ALAMY