Dicksonia antarctica - Tree Fern

Dicksonia antarctica is an arborescent fern, forming a silky trunk topped with a lush, tender green foliage that gives it a strong exotic appearance. It is undoubtedly the hardiest species of the genus.

In nature, this arborescent fern can form a trunk 10 m to 15m (32.8 ft to 49.2 ft) tall and measuring up to 50 cm (19.7 in) in diameter. Away from its natural habitat, it rarely exceeds 5 m to 6 m (16.4 ft to 19.7 ft) in height.

Its fibrous trunk (stipe), brown in colour, measures on average 25 cm to 30 cm (9.8 in to 11.8 in) in diameter, and is traversed by a dense network of black capillary roots. Its growth is slow, averaging 2 cm to 5 cm (0.8 in to 2 in) per year, but its lifespan is extremely long.

The fronds (leaves) of the Dicksonia antarctica are carried at the top of the trunk and measure from 2 m to 3 m (6.6 ft to 9.8 ft) in length, forming a large, spreading tuft that can measure up to 5 m (16.4 ft) in diameter. With a tender green colour, the fronds are tripinnate, shiny, soft to the touch, and have a significant layer of brown bristles at the base. They are evergreen and each has an average lifespan of 2 years when not exposed to severe frost, otherwise they "burn" in winter and are replaced by a new crown of fronds the following spring.

Arborescent ferns are not known for their great hardiness. However, some species, notably Dicksonia antartica and D. fibrosa, are quite hardy without any protection down to -7° C (19.4° F), and even down to -10° C (14° F) if they are in a calm, sheltered location.

Beyond that, winter protection is necessary. It can be as simple as a "straw hat" to shelter the future fronds at the top of the stipe, which is the most sensitive area to the cold. This way, the fern can withstand temperatures down to about -12° C (10.4° F) for a short period. Another solution is to cultivate them in a large pot and bring them indoors in winter in an unheated or minimally heated conservatory.