Dicksonia antarctica

A soft tree fern from southeastern Australian rainforests

Dicksonia antarctica is native from southeastern Queensland through New South Wales and Victoria to Tasmania. Its apparent trunk is an upright fern stem wrapped in old frond bases and a dense mantle of fibrous roots.

Wild plants grow in rainforest and wet eucalypt forest, especially in sheltered gullies and beside creeks. High rainfall, cool humid air and deep shade allow large fronds to spread beneath the tree canopy. Mosses and smaller ferns often take root in the damp, fibrous trunk.

Moisture and airflow for healthy fronds

Crown and old fronds

Give the frond crown ample room; it needs no stake if the heavy pot and roots are stable. Avoid cutting the trunk or damaging the coiled new fronds in the centre.

Water for both root ball and trunk

Keep the root ball evenly moist at all times. A large frond crown, warmth, sun and a small pot raise demand substantially.

Cooler conditions for a living fibrous trunk

A cool-to-mild indoor position is preferable. Established plants tolerate lower temperatures when protected and freely drained.

Humidity through a broad frond canopy

Moderate to high humidity helps the fronds unfurl fully and reduces dry leaflets. A humidifier is more effective than misting; if the trunk is wetted during watering, let the fronds dry steadily afterwards.

Dilute feeding for an expanding frond crown

Developing tree-fern fronds can be fed with balanced complete fertiliser at a low dose. Continue lightly through winter only if warmth and light keep new fronds growing and the plant remains thirsty; a cool resting plant needs little or none.

When Dicksonia antarctica fronds or croziers fail

Old fronds brown after winter or frost

Existing fronds can be damaged while the protected crown survives. Wait until the weather settles, then remove only fully dead fronds and check the crown for firm curled croziers. Avoid assuming the trunk is dead from brown foliage alone. A black, loose or foul-smelling crown is much more serious.

Croziers begin to unfurl, then dry or stop

The crown or fibrous trunk may have dried during active growth, or late cold may have injured the tender flush. Check moisture through the root zone and trunk, shelter the crown from extremes and keep conditions steady. Avoid pulling open a stalled crozier. Soft black tissue strongly suggests rot and needs prompt attention.

Large fronds are shredded or bent

Wind and repeated contact easily tear the broad fern canopy. Mechanical splits are dry and stop at the damaged section; they do not spread between fronds. Move a container to a sheltered site and support it securely. Keep partly green fronds because they continue feeding the crown.

The crown becomes black, soft or hollow

Crown rot is urgent because all new fronds arise from this single growing point. Remove loose dead material without gouging healthy tissue, prevent cold water from sitting in a damaged winter crown and seek specialist treatment if firmness is being lost. A destroyed crown cannot simply reshoot from an ordinary side bud.

Each new flush is smaller than the last

Repeatedly small fronds can indicate that the large root system or moisture-holding fibrous trunk is drying, that the plant remains too dark, or that roots were restricted during establishment. Check those physical conditions first. Continued decline with a shrinking crown calls for a root and trunk inspection, not stronger feed.

Dicksonia antarctica is non-toxic to cats and dogs

• This plant is non-toxic to cats and dogs.
• Its effects on people are unclear, so keep it away from young children who may chew it.
• Eating a large amount can still cause an upset stomach. Seek medical or veterinary advice if symptoms continue.

About the name Dicksonia antarctica

Dicksonia honours Scottish botanist and nurseryman James Dickson. Antarctica means southern here.

Charles Louis L'Héritier de Brutelle established the genus Dicksonia in 1789 in Sertum Anglicum, page 30.

Jacques Julien Houtou de Labillardière first described Dicksonia antarctica in 1806 in Novae Hollandiae Plantarum, volume 2, page 100.