Tree ferns are a plant capable of giving your garden that vibrant tropical look or they can equally provide that mysterious insight into what the forests of the earth looked like before flowering plants evolved. Carbon dating techniques have found tree ferns can be dated back to the Jurassic period. The plants are unique instead of having a woody stem covered in a protective bark the trunks of tree ferns are composed of rhizomes modified to grow vertically and covered with a dense miss-mash of roots. These trunks may reach heights of 20 metres (65 feet) or more in species such as Cyathea brownii. At the top of the trunk there is a growing tip which produces a cluster of often highly divided fronds that can be several metres in length. The fronds act as leaves and help the plant perform photosynthesis.
The picture below is a common scene in sub tropical regions. Cyathea cooperi tree ferns growing at Cairns Botanic Gardens, Australia. The fronds are glistening in the afternoon sunshine.
Cyathea cooperi is one of the most common tree ferns found in sub-tropical regions as it is relatively fast growing and quick to establish. Believe it or not this species of tree fern is considered an introduced pest and threatens many native Cibotium tree fern species on the Hawaiian Islands. More information
Probably the most commonly grown tree fern in the Northern hemisphere is Dicksonia antarctica. This species is also considered one of the most tolerant of cold conditions surviving temperatures as low as -10°C (14°F). The first Dicksonia antarctica came into the UK at the end of the 20th Century aboard ships returning from Australia. The ships used tree fern trunks as ballast or weights in their holds to prevent cargoes moving about in heavy seas. At docks around the South West of England the trunks were discarded on the quayside when ships were unloaded. It was here that people noticed these trunks were growing new fronds and that, in time, the ends of the trunks were turning upwards and starting to regrow towards the light.
Nowadays it is common for tree ferns such as Dicksonia antarctica to be sawn of top and bottom just leaving the trunk in the same way as the first ships did, however today the trunks turn up at your local garden centre and their not cheap! Some of the oldest tree ferns in the UK can still be found at gardens such as Trewidden and The Lost Gardens of Heligan. More information
There are three main families of tree fern Cibotium, Cyathea and Dicksonia. If you are interested in finding out more information on tree ferns have a look through and fern files.
Cibotium is a small family of eleven tree ferns, with species found in Hawaii, South East Asia and Central America. Only a handful of species are in cultivation but they do add great interest to any tree fern collection. The name Cibotium is derived from the Greek kibotion, a small box often used to hold medical remedies. Cibotium glaucum, from Hawaii, is the most common Cibotium species found.
Cyathea is the largest family of tree ferns, with 500+ species. The word Cyathea comes from the Greek kyatheion meaning ‘little cup’ referring to the sori found on the underside of fronds. The Cyathea genus of tree ferns includes the world’s tallest tree ferns, which can reach heights in excess of 20m.
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 tend to be slow growing ferns often with large trunks which in some species can reach in excess of 1m in diameter.