Cyathea dealbata
"Ponga"
"Silver Tree Fern"
This magnificent tree fern comes from the dense, lush forests of New Zealand. Its most prominent distinguishing characteristic is that the fronds are a beautiful silver-white underneath, and the stipes are silvery as well. Other than that it is reasonably similar to C. australis, though it prefers more shade and shelter. The silvery fronds make it an exceptionally superb subject for night lighting. It is extremely rare in cultivation outside of Australia and New Zealand.
The arching fronds are very large, sometimes up to 12', and form a beautiful, full, dense crown. Trunk development begins rather slowly compared to some other species, and the fronds on young plants may not be silvery.
Although it shows a definite preference for moisture and cool conditions,
it does seem somewhat adaptable and relatively easy to grow even in relatively
dry conditions (as ferns go). Some plants can be a bit cold-hardier
than commonly thought, as it does range well into the mountains of New
Zealand's South Island, and good provenances may be able to withstand temperatures
around 22°F (perhaps lower) without any trouble. One specimen
grew well for many years at Logan Botanical Garden at Stranraer, Scotland,
and even recovered from a temperature of 14°F on one occasion.
It should be able to grow well in the Pacific Northwest and Britain with
the standard protection measures. As far as I am aware its heat tolerance
remains untested, but it is worth trying in hot climates.
Cyathea dealbata in New Zealand, photo courtesy of Ralph Booth. The crowns can contain a great many fronds.
Cyathea dealbata in New Zealand, Photo courtesy of Ralph Booth. The undersides do not appear silvery in this photograph since it is silhouetted against the sky.
Cyathea dealbata at Fancy Fronds Nursery in Gold Bar, Washington. Note the silvery stipe and the silvery underside of the frond. Photo by the author.
Croziers, stipes and fronds of a potted Cyathea dealbata at Fancy Fronds Nursery, Gold Bar, Washington. Photo by the author.
Stipes and crown of Cyathea dealbata at Fancy Fronds Nursery. Photo by the author.
Top view of Cyathea dealbata crown at Fancy Fronds Nursery; photo by the author.
Uncurling crozier of Cyathea dealbata at Fancy Fronds Nursery. The scales of this species are a stunning contrast to the stipes. Photo by the author.
Cyathea dealbata, a young plant in Australia. Photo courtesy of Scott Ridges.
Close-up of the upper trunk and stipes of Cyathea dealbata. Photo courtesy of Peter Richardson.
Cyathea dealbata in habitat in New Zealand. Photo courtesy of Peter Richardson.
Crowns of Cyathea dealbata in habitat in New Zealand. Photo courtesy of Peter Richardson.
Cyathea dealbata in habitat on New Zealand's North Island. Anonymous photo.
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