Cyathea medullaris - Black Tree Fern

Cyathea medullaris is a species of arborescent tree fern with spectacular and rapid growth. It will immediately bring a touch of exoticism to your garden, terrace, or patio. It prefers moist but well-drained soils that are rather acidic and rich. Plant in partial shade or non-burning sun. It is frost-sensitive, tolerating only very short frosts down to -3°C (26.6°F).

Cyathea medullaris belongs to the Cyatheaceae family. Members of this family are found in Oceania and the Pacific Islands, and appreciate humid forests with soft soil. Air humidity is also very important, which is why these ferns wither in wind and dry atmospheres. This species, mainly from New Zealand but also found on a few islands, is also known as the black arborescent fern, due to its magnificent "trunk" (called the stipe in these plants, it is actually the remains of roots and the petiole of old fronds) which is slender, and covered in black and shiny scales. At the top of the stipe, the superb evergreen fronds are produced. They are apple green with reddish hairs, and unfurl like a crozier as they grow. Forming a vast and elegant crown, they can reach 2 to 4m (7 to 13ft) in length. The development of this cyathium is quite rapid, and it can reach 5m (16ft) in height and 3m (10 ft) in width under favourable conditions (with an annual growth of about 30cm (12in)) - in its native habitat, it can exceed 20m (66ft) in height!

It should only be grown in mild regions. It needs moist but well-drained, acidic and not too rich soil. It requires a stable climate that is neither too hot in summer nor too cold in winter. The fronds suffer below 0°C (32°F), and the plant can die from -3 to -5°C (26.6 to 23°F). It tolerates light sun, although it prefers partial shade. It is possible to protect it by placing it in a very sheltered spot, in a winter garden if it is in a container, or by placing a winter covering (possibly heated) around the stipe during cold periods. Furthermore, it dislikes drying winds and absolutely requires high atmospheric humidity. Its cultivation therefore requires some expertise, and we would not recommend it to a beginner gardener. Successfully growing this plant will be a great achievement! It will continue to attract the attention of your visitors and will be a centrepiece of your garden.