Cyathea brownii, commonly known as the Norfolk tree fern or smooth tree fern, is probably the largest tree fern species in the world.
It is endemic to Norfolk Island, in the Pacific Ocean near Australia and New Zealand.
In natural habitat Cyathea brownii can reach up to 20 metres or more in height. The broad, lance shaped, bipinnate-pinnatifid to tripinnate fronds can reach 5 metres in length. The stipe is long and has a line of white, stitch like dashes along its length. Rachis and stipe are covered in white-brown and darker orange-brown scales. The trunk can become smooth with age and may display oval scars left from fallen fronds.
This spectacular tree fern enjoys a sunny position. Planted in a semi shade position, and protected in winter, this plant will makes a fine addtion to any garden.Tree ferns should be planted in a semi-shaded position out of strong midday sunshine and chilling winds. The plant will become more tolerant as it matures. You will also need to consider the eventual size of the species when planting as they quickly form a trunk and do not like to be moved.
Tree fern need lots of water. Young plants can consume 1-2 litres a day so make sure it is a position where you can access the plant to water it every day. Drainage is important as the plant will not tolerate being waterlogged. Therefore getting the soil drainage correct is the key. A good humus open compost with lots of organic matter and high in nutrients is best.
Dig a hole 1m in diameter and 60-80cm in depth and fill this with drainage material like rubble and then cover in gravel to stop the top soil washing through. Then fill the whole with your compost securing the plant whilst trying not to compact the compost to much. To achieve this you may want to stake the plant if it is trunked to provide extra stability whilst the plant establishes its root system.
This species is difficult to grow in colder climates as the speed at which it grows means within a few years it become difficult to protect over winter in a greenhouse or conservatory.