The Dicksonia family includes some of the most important and now widely cultivated tree ferns in Europe and North America. The family only has around 25 species, compared to the 500+ Cyathea species.
The Dicksonia family is named in honour of James Dickson (1738-1822), a prominent British nurseryman. It is thought that the link between James Dickson and tree ferns came from his friendship with Sir Joseph Banks (1743 –1820) who took part in Captain James Cook’s first great voyage ‘Endeavour ‘ (1768–1771). Banks was known to have collect spores of Dicksonia arborescens in St. Helena during the ‘Endeavour’ voyage. But it was French botanist Charles-Louis L’Héritier (1746-1800) who first described and named the genus Dicksonia in Sertum Anglicum 1788.
Dicksonia species are distributed from Mexico to Uruguay and Chile, St. Helena, New Zealand, Australia, Indonesia and New Guinea. The most widely cultivated are Dicksonia antarctica and Dicksonia fibrosa. These species have grown in popularity over recent years as a plant of ‘architectural’ choice with well established mature specimens able to survive frosts down to -10°C.
Dicksonia and Cyathea species are related, although Dicksonia is considered to be more primitive, dating back at least to the Jurassic and Cretaceous periods. The species can be distinguished in several ways firstly the fronds are usually coarser and look less waxy; secondly the croziers are covered in fine hairs rather than scales. The individual fronds are more convex as opposed to the often flat fronds of many Cyathea species.
The Dicksonia family tend to be slow growing ferns often with large trunks which in some species can reach in excess of 1m in diameter. Dicksonia squarrosa native to New Zealand is an exception to this rule and tends to be quite fast growing with a slender trunk. The main trunk of this species fern often dies when it reaches around 2m due to its constant need for moisture found around the forest floor, when the main trunk dies new growth often appears from the bottom of the plant.
Another unusual species is Dicksonia lanata which is also found in New Zealand. This species has to forms one which can grow a slender trunk up to around 1m and another which is clump forming. The species is relatively rare but well worth trying from spore as it should be as hardy as Dicksonia squarrosa.
One final species of note is Dicksonia sellowiana this species can be found in many parts of South America in damp forest at elevations of between 750-2250m. The species is very similar to Dicksonia antarctica and Dicksonia fibrosa and should have a similar tolerance to frosts. The species is easy to grow from spore and adds something different to a fernery.