Cyathea medullaris

Source: Gerald.w

Cyathea medullaris

Cyathea medullaris or Black Tree Fern is a large tree fern which is only slightly hardy and will not survive frost, except in particular micro-climates with adequate care.

It should be overwintered in a cool greenhouse.

It is a fast grower and its black shiny leaf base and size make it a dramatic landscape plant.


Cyathea medullaris is an evergreen fern that reaches up to 20 m high. Its trunk is slender and black, covered with distinctive hexagonal stipe scars. It can attain 60 cm in diameter at the base

The fronds may be up to 5 m long, they arch upwards from the crown. The upside of the frond is dark green and shiny, the underside is a paler green. The primary pinnae are from 40 cm to 1 m long, and the undersides bear scales with marginal spines. New fronds form a fiddlehead and are covered in thick black hair.


The trunk is used as building material.


Common names:

Black tree fern, king fern, mamaku, katātā, kōrau or pītau (Maori)


Alsophila extensa, Alsophila lunulata, Cyathea affinis, Polypodium medullare, Sphaeropteris medullaris


Cyathea: from the Greek kuathos (cup)
Medullaris: from the Latin medulla (marrow, pith)

Cyathea medullaris frond

Source: Dinkum

Cyathea medullaris frond


New Zealand, Fiji, Polynesia


Lowland forest, from 0 to 600 m altitude


USDA zone 9, -4 °C



Well drained, humus-rich soil


Partial shade, shade


Keep moist, water daily in summer

Cyathea medullaris fiddlehead

Source: Gerald.w

Cyathea medullaris fiddlehead



Sowing instructions:

  • any time of the year
  • surface sow in a light position, the spores need daylight at all stages
  • 20-25 °C
  • keep moist at all times, eventually place in a plastic bag to avoid evaporation of water
  • germination time: 1-6 months


  • partial shade, keep out of direct sunlight
  • keep roots and the trunk wet at all times
  • can easily be grown in a pot
  • may be kept outside during summer but has to overwinter sheltered from frost, in a cool room or cool greenhouse