Tree fern (Dicksonia antartica)

An ancestral plant in the garden.

Culture sheet: when and how to plant a tree fern?

Family: Dicksoniaceae.
Dimensions : in nature, the plant can reach 15 m in height. In our climates, it will reach 5 to 8 m, after many years.
Distance and depth of planting: in the ground, the plants must be separated by about 3 to 4 m so that the fronds spread out well without being hampered. Plant the fern in the spring when the earth has started to warm up. Planting is possible in the fall in mild climates.
Growth: it is very slow, the trunk, called the stipe, growing every year by only 3 to 5 cm.
Appearance: this fern is a sight on its own. Its massive and upright trunk is formed by the successive layering of the fronds (leaves of the ferns). Its root system is aerial, surrounding the trunk with a brown felting. It is he who captures the humidity and mineral salts necessary for the growth of the plant. In May-June, the fronds appear at the top of the trunk. Rolled up in butts inside, they unfold in erect fronds which then take on a spreading habit, then falling. They are a beautiful shiny green and their petioles bear red hairs. At the end of summer, they reach a length of 1.50 to 2 m.
Soil : The quality of the soil is of little importance because the tree fern has few underground roots.
Exposure: a semi-shaded situation will be perfect. Choose a place protected from the winds by walls or hedges because the very long fronds break easily.
Climate : placed outdoors, the tree fern supports colds of around – 15 ° C provided it is well protected.

Origin: where does the fern come from?

The genus Dicksonia comprises about thirty species distributed in the mountains of Malaysia, Australia, New Caledonia, New Zealand. D. antartica appeared on Earth about 350 million years ago, as can be seen from fossils dating from the Carboniferous period. The genus is dedicated to James Dickson (1738-1822), an English botanist, author of several works including one on ferns .

What are the different species and varieties of fern?

Only D. antartica can be grown in open ground in some areas. There are superb specimens on the west coast of Scotland and in English Cornwall, humid areas protected from the cold by the Gulf Stream. Other tree ferns, smaller, adapt to container culture, which allows them to be sheltered in winter. This is the case of D. fibrosa and D. squarrosa which reach about 6 m in nature, but hardly exceed 1.50 to 2 m in our climates.

How to use and associate ferns in the garden?

In the ground, a single copy of tree fern is enough to give an exotic atmosphere to the garden. accompany it with plants with remarkable foliage such as hostas, astilboides tabularis, ornamental rhubarb, chestnut leaf rodgersia.

Culture: where to plant a tree fern?

In the ground or in a pot, it is very simple. You have to push the base of the stipe more or less deeply (it depends on the size of the plant) so that it is quite stable. The earth serves only as an anchor point .

How to maintain a tree fern?

The element that the tree fern needs the most is humidity in the air , which must be very important. On the coasts of the Breton or Atlantic coast, in Normandy, she is at her ease.

How to water the fern?

Elsewhere, it should be regularly given water by sprinkling it in the heart of the fronds and by wetting the fibers of the trunk well. As winter approaches, it will be necessary to protect it if it stays outside.

How to prune a tree fern?

Start by cutting the fronds, then surround the trunk with a coarse mesh netting, all the way up to the stem. Close this “tube” with strong ties, then slide handfuls of dead leaves between the trunk and the wire frame. Firm enough to obtain good insulation. Finish by attaching a piece of transparent plastic to the head of the plant with a string. Remove this protection in April.

How to multiply a fern?

It is possible by sowing, but this technique is reserved for very patient gardeners! Like all ferns, D. antartica produces seeds (spores) which develop under the fronds. When they’re brown, it’s time to seed them. To do this, spread a piece of frond on the surface of a box containing potting soil. Hold the slingshot with the help of small jumpers. Place everything in a warm and especially humid greenhouse.