Black Tree Fern (Cyathea medullaris): Majestic New Zealand Giant with Black Trunk

Overview

The black tree fern (Cyathea medullaris), known as mamaku or korau in Māori, is the **tallest tree fern in New Zealand**, reaching 50–65 feet in the wild. Its massive, black, rough trunk—covered in hexagonal leaf scars—supports a vast crown of arching, dark green fronds up to 15–20 feet long. The thick, starchy pith of the trunk was a traditional food source for Māori. A true giant of the temperate rainforest.

Imposing Features

• Black Trunk: Distinctive, dark, scarred trunk is unmistakable.
• Massive Scale: Among the largest tree ferns globally.
• Cultural Significance: Important food and fiber plant for Māori.

Culture

Partial shade; deep, moist, fertile, well-drained soil. Shelter from wind. Water trunk and crown copiously. Frost tender below 25°F (-4°C); USDA zones 9–11. Requires space—plant as a specimen in large gardens or parks.

Taxonomic Profile

A sovereign presence in the landscape, the black tree fern embodies primeval grandeur.