The botanical name Dicksonia sellowiana derives from:
Dicksonia – named in honour of James Dickson, 1738-1822, a British nurseryman.
sellowiana- named after Friedrich Sellow (1789-1831) a German botanist and naturalist who was art of a botanical expedition to Brazil by Prinz Maximilian zu Wied.
Dicksonia sellowiana is endemic to South America, growing from Southern Mexico to Argentina. The preferred habitats of Dicksonia sellowiana are wet forests, montane rain forest, along streams, and at higher altitudes in cloud forests. Typically in these habitats the species can be found at altitudes of between 750-2250m
Due to its varied distribution and habitat and limited cultivation its exact hardiness is not known although some feel it should be as hardy as Dicksonia antarctica surviving temperatures as low as -13°C (8°F). I would be cautious with this though and if left outside in frost prone regions give extra protection. Dicksonia sellowiana is not as widely harvested as its Australian or New Zealand relatives and therefore mature trunked specimens are in short supply.
Dicksonia sellowiana is variable in its form which isn’t surprising given the area and variability of its habitat. These variations in the species are sometimes treated as separate species our varieties of Dicksonia sellowiana, these include:
Dicksonia sellowiana var. ghiesbreghtii
Dicksonia sellowiana var. gigantea
Dicksonia sellowiana var. karsteniana
Dicksonia sellowiana var. lobulata
Dicksonia sellowiana var. gigantea is the most common and is often referred to as Dicksonia gigantea and is found in Mexico. The variety often forms a much larger trunk in both diameter and height. Similar to Dicksonia squarrosa the plant sends new suckers up from its base often forming a small clump.
Dicksonia sellowiana is very similar in appearance to Dicksonia antarctica. There are two subtle differences, unfurling fronds as well as around the base of stipes are covered with dense yellowish hair when new fronds are emerging, the second difference is that new fronds keep emerging throughout the growing season rather than in several flushes.
The species can grow up to 10m x 15cm (33ft x 6in) in height; it has large dark green roughly textured fronds growing to 3m in a spreading canopy of up to 6m (20ft) in diameter. Dicksonia sellowiana is a very slow growing specimen. The trunk itself is made up of a central core of very hard woody vascular tissue. This is surrounded by old leaf bases through which root fibres grow.
The condition in which Dicksonia sellowiana will flourish is a moist and semi shaded location with a sufficient amount of water but well drained soil with lots of organic matter and plenty of water. The older the plant the more tolerant it will be to other situations.
Before planting the trunk, it is recommended that it should be soaked in water for a few minutes. Dig a hole slightly larger than the diameter of the trunk and infill with organic mulch. Plant the log in such a way that as little trunk as possible is buried, while ensuring that it is stable and will not easily topple over easily. Once the trunk is firmly in place, water the trunk copiously.
The most important maintenance of Dicksonia sellowiana is regular watering. At sizes less than 1ft this should be several times a week and daily for the first summer to establish a good root system. Do not spray directly in the ferns crown (top) as in colder weather this may encourage rot. Instead soak the whole trunk, angling the hose from below, the wetter the better.
For aesthetic reasons it may be necessary to remove old fronds in the spring, this does not necessarily benefit the plant which subsequently becomes more exposed and susceptible to drying out.
There are three main strategies for providing winter protection to tree ferns: keeping them in a conservatory all year round; overwintering small plants in a protected environment; and protecting larger plants outdoors in situ.
Overwintering smaller plants carefully is important as they are more prone to die if frosts are heavy. Where possible it is advisable where possible to bring any plants 2ft or less into a cool conservatory, greenhouse, or even a shed, where temperatures will be higher. It is also desirable to cover the plant with fleece on those nights with hard frosts for added protection, but remember to continue water the trunks once or twice a month.
Larger plants, although more hardy, still need some protection. The easiest way to provide this is to is to compact a good amount of straw in the crowns of the ferns to stop ice from freezing the crown. In plants less than 4ft added protection may be necessary by insulating the trunk with polystyrene plants trays belted around the trunk.
Family Name: Cyatheaceae.
Position: Partial to full shade.
Soil: Humus-rich, neutral to acid soil.
Growth Rate: Slow.
Eventual spread: 6m.
Max Height: 10m.
Hardiness: Half Hardy – reputedly hardy down to -10°C with the foliage hardy to -2°C.
Winter tips: Protect crown from frost by insulating with straw bound chicken wire.
Summer tips: Keep plants moist, water daily during the hotter periods.