Tree Fern, Australian treefern
Dicksonia antarctica
Family: Dicksoniaceae
What it is like
Dicksonia antarctica is an evergreen Fern growing to 9 m (29ft) by 4 m (13ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 8 and is frost tender. It is in leaf all year. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland). It prefers moist soil.
Height (m): 9
Where it is found
Damp sheltered woodland slopes and moist gullies.
Australia - New South Wales, Tasmania, Victoria.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 1
The pith in the upper part of the trunk just below the growing point is eaten raw or roasted. It is rich in starch but also contains tannin and is astringent. Descriptions of the taste vary from bitter to sweet, astringent and like a bad turnip. The core of the plant near the growing tip is used. Harvesting the stem kills the plant so this use cannot normally be condoned. The stem contains about 61 kilocalories per 100g. Young leaves - cooked. Harvested just before they unfurl, they are juicy and slimy, tasting like bitter celery.
Stem: this often intergrades into leaves.
Medicine
Rating: 1
Astringent.
Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
Other
Rating:
This species is used in New Zealand to stabilize roadside cuttings.
Soil stabilization: Plants that can be grown in places such as sand dunes in order to prevent erosion by wind, water or other agents.
How it is grown
Requires a sheltered woodland position and a moist soil. Strongly resents drought or dryness at the roots. A very ornamental plant, it is hardy to about -5°c, succeeding outdoors in the milder areas of Britain where it thrives and often self-sows in Cornish gardens. One report says that some forms are hardy to at least -7°c. Plants can tolerate snow but are intolerant of severe frosts. Members of this genus are rarely if ever troubled by browsing deer. The 'trunk' of this plant is merely the decaying remains of earlier growth of the plant and forms a medium through which the roots grow. Plants can be cut down and, if they are kept moist, the top portions can be replanted and will form new roots. The stump, however, will not regenerate since it is simply dead organic matter. It is best to leave old fronds on the plant in order to protect the trunk from cold and desiccation.
Propagating it: Spores - can be sown at any time in a warm greenhouse. Surface sow and enclose the pot in a plastic bag in order to keep it moist. Place in light shade. Germinates in 1 - 3 months at 20°c. Prick out small clumps of plants when they are large enough to handle and grow on in a shaded part of the greenhouse for at least the first 2 years. Plant out in late spring after the last expected frosts. The spores can be stored dry for up to 10 years.
Best place to grow: Woodland Garden Dappled Shade; Shady Edge;
Habit: Fern
Hardiness: 7-10
Growth: Slow
Soil: Light (sandy), medium, heavy (clay)
Shade: Semi-shade
Moisture: Moist
Things to keep in mind
Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable. Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase.