Credit: David Foley
Dicksonia antarctica
Background and story
The Soft Tree Fern (Dicksonia antarctica) is one of the most iconic tree ferns, native to the cool temperate rainforests of southeastern Australia and Tasmania, where it grows in damp, shaded valleys and along streams.
Introduced to Ireland and Britain in the 19th century, it quickly became a centrepiece of Victorian fern collections and remains one of the most widely cultivated tree ferns today.
Its slowly developing trunk, formed from a mass of fibrous roots, supports a crown of graceful, arching fronds, giving it a distinctly lush, prehistoric appearance that has long appealed to gardeners seeking a woodland or exotic atmosphere.
Did you know?
It isn’t really a tree at all. What looks like a trunk is actually a mass of matted roots and old frond bases wrapped around a central stem (caudex), rather than true woody tissue.
Hardiness and conservation
The recorded RHS hardiness rating is H3, which means this plant is generally hardy in coastal and relatively mild districts, especially where drainage and shelter are good. The recorded USDA/PFAF hardiness value is 7-10, which is useful as a broad winter-temperature guide, but it should not be read as a direct substitute for the RHS rating. Local hardiness always depends on local shelter, drainage, winter wet, salt-laden wind and the plant’s age and establishment.
The IUCN Red List status recorded here is Not Assessed (NA).
Additional notes for Ireland and Britain
In Ireland and Britain, Dicksonia antarctica is relatively hardy and reliable, particularly in mild, sheltered gardens with consistent moisture and shade. It thrives in humus-rich, well-drained soils and performs especially well in damp, sheltered corners where its fronds are protected from wind. Growth is slow, often producing only a few centimetres of trunk each year, but over time it can reach 2–5 metres or more. Winter protection, particularly of the crown, can improve survival during colder spells, though in many Irish coastal areas it can grow successfully with minimal intervention.
From a conservation and hardiness perspective, Dicksonia antarctica is not currently considered threatened, though it has been affected in the past by over-harvesting of wild plants, particularly for export. Today, most plants in cultivation are nursery-grown, reducing pressure on natural populations. In terms of hardiness, it tolerates moderate frost (typically down to around −8°C to −10°C), especially if the growing point is protected and kept from prolonged freezing. Its main vulnerability is cold drying winds and severe frost, rather than moisture, provided drainage is adequate. In an Irish context, it is one of the most successful and rewarding tree ferns available, offering a strong exotic effect with relatively manageable requirements.
Notable features
- It is an ancient plant lineage. Tree ferns represent a group that dates back hundreds of millions of years, predating flowering plants and surviving since the age of the dinosaurs.
- It grows extremely slowly but can live for centuries. Typical growth can be only a few centimetres of trunk per year, and mature specimens may take decades to reach full height and can persist for very long periods.
- It reproduces without flowers or seeds. Like all ferns, it produces millions of microscopic spores on the underside of fronds, a reproductive system that has remained essentially unchanged for millions of years.
- Its trunk can support an entire miniature ecosystem. The fibrous stem retains moisture and organic matter, allowing mosses, smaller ferns, and other plants to grow on it, effectively turning the plant into a living habitat.
Earlscliffe notes
We have a large number of Dicksonia antarctica around the garden, many of which are quite old.