Friday, April 3, 2015

Tree Ferns

The local treeferns will be loving all this rain!
These lovely, lacy fern-umbrellas are wonderful in a shady garden, and some will tolerate a considerable amount of sunlight. It’s a matter of choosing the right species.
We have two local treefern genera – Cyathea and Dicksonia. Of the two, Cyatheas tend to be hardier in our part of the world, and are therefore popular in cultivation.
Unlike Dicksonia antarctica, whose trunk is  covered with soft red-brown hair, the Cyatheas have scales. This surprises me, as what are apparently long narrow scales look like coarse hairs, to me. However, they contrast with the soft hair of the Dicksonia, which is rather nice to touch.

Rough Tree Fern
Cyathea australis

This may be the best treefern for local gardens. It is hardiest local tree-fern, the most widespread in nature (in our district) and the most commonly grown in gardens. It is the best for tolerating sunshine, drought and (light) frost, and can even regenerate after fires.
It was probably once quite common in the Toowoomba area, in the shady forests on both sides of the range. While tree ferns are usually thought of as rainforest plants, this one also grows in the wetter Eucalypt forests.
It is a tall, stout and sturdy plant. Its "roughness" comes from the blunt prickles on the leftover frond bases which clothe the trunk. Its red-brown scales distinguish it from our other local Cyathea species which has straw-coloured scales.

It can be rather slow-growing, but watering, and mulching to keep the soil moisture level reasonably high helps it grow faster.

Coin-spot Tree Fern
Cyathea cooperi  

This species may also have once been common in Toowoomba. A few naturally occurring plants still exist in a stream on the south-west side of Mt Kynoch, which flows into Gowrie Creek. It is considered to be a plant of wet rainforests, so these rather surprising survivors, now growing in a closed forest consisting mostly of privet, probably indicate that Gowrie creek itself used to flow through lush rainforest.

Almost as hardy as Cyathea australis, it differs in having a slender trunk, whose the leaf bases usually (but not always) fall off, leaving large, smooth oval spots which give it its common name.
The bases of the leaves have a distinctive curve, which give the plant a crown unlike any other local species.

Though it is happy with its head in the sun, it prefers a cool, shady, well-mulched root-run, with as much water as the garden-owner can afford to give it.Given these conditions, it is our fastest-growing treefern species.

Soft Tree Fern
Dicksonia antarctica  

This is our thirstiest local tree fern. In our district, we find it only in the damper rainforests on the edge of the Great Dividing Range.
It can be distinguished from our other treeferns, the Cyathea species, by the softness of its red-brown hairs.
It reminds me of an orangutan, but Tasmanians know it as a  "man fern", apparently because the thick trunk is so often about the size and proportions of a man. While there are plenty of upright specimens, the plant often leans, or simply lies down.

The hairy trunk provides niches for lots of little epiphytes, especially little ferns. This could be used to great advantage in a damp garden. Unlike the Cyatheas, this plant absorbs water through its trunk, so it is often grown with help from automatic sprinklers.
In the wild, it has suffered from the fact that it can be transplanted simply by cutting off the trunk at ground level, planting it in its new site, and watering it well. The temptation to plunder nature for a plant which is worth quite a lot of money is too difficult for some people to resist. Unfortunately, in the Australian climate, with its regular droughts and water restrictions, it has proven too easy to kill before it has become properly established.
While it is a lovely plant, its water needs mean that gardeners might feel that one of the Cyathea species is a more environmentally friendly choice.

All three of our local tree fern species grow in the Bunya Mountains, and all of them can be seen at different points beside the short walking track from the Dandabah car park to the Festoon Falls.

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