The Silver Tree Fern ( Cyathea dealbata ) is a beautiful tree fern that is native to New Zealand and is easily recognised by the silvery-white colour on the underside of its mature fronds. In New Zealand this species is well known and used as a symbol. Among many places, it appears on their coat of arms, their national air line and as a name and logo for sporting teams, including the famous ‘All Blacks’.
Cyathea dealbata is a tall tree fern that is quite cold tolerant and has been successfully grown in countries like Ireland. However, frost will damage the fronds of this fern and consistent frosty temperatures below -6°C could severely damage this plant. The Silver Tree Fern copes better than many ferns in drier areas and can cope with temperatures up to 34°C, as long as it is in a well shaded position.
Growth
The trunk of the Silver Fern can grow to 10 metres tall and 45 cm’s in diameter. As mentioned above, the easiest way to identify this tree fern is by the underside of mature fronds, the broken bases of old fronds (stipes) that remain attached to the trunk, also have the same silvery-white colour.
The fronds of Cyathea dealbata can grow as large as 4 metres long, giving the fern a large canopy of up to 8 metres. A shaded spot either in a fernery type location, under a patio or under the shade of other larger trees is best. It does not like full sunlight and if placed in these conditions; its gorgeous fronds will burn and die off. This species can survive well in temperate zones outdoors if in a position protected from frost and cold winds; again keeping its natural habitat in mind, where it is protected by larger canopy trees.
FAMILY:
Cyatheaceae
CLIMATE:
Cool Temperate to Sub-Tropical
TEMPERATURE RANGE:
-6 to 30°C / 21 to 86°F
SOIL TYPE:
Humus rich, moist soil
LOCATION:
Full Shade – Dappled Shade
HEIGHT:
Up to 10 metres (32 feet)
WIDTH:
Up to 8 metres (26 feet)
pH:
5.5-7.0
GROWTH TYPE:
Evergreen
WATER REQUIREMENTS:
Medium.
POLLINATION:
Spores form on the underside of the fronds, which have both male and female organisms present.
MATURITY:
2-5 years
GERMINATION RATES:
75-86%
GERMINATION TIME:
Germination process will usually begin around 2-6 weeks, however it may be many months before they start to look like little ferns.
SEEDS PER GRAM:
Too many to count – well into the hundreds of thousands.
MEDICINAL QUALITIES:
No
WEED POTENTIAL:
No
FACTS ABOUT CYATHEA DEALBATA (NZ Silver Fern)
Although it is reasonably cold tolerant, its fronds can freeze and die away in frosty conditions, however will generally begin to grow back once the weather improves in spring.
Maori’s call this species Ponga or Punga and the Maori flag displays a symbol of an unfurling Silver Fern Frond.
This species has another synonym Alsophila dealbata.
