Cyathea medullaris – The Black Tree Fern
- Mandy Braam
- Jul 3
- 2 min read
The Cyathea medullaris is a striking tree fern known for its dark trunk and large, elegant fronds. In this blog, you'll learn more about its origin, appearance, and how to care for it properly.
Where does Cyathea medullaris come from?
This tree fern is native to New Zealand and several Pacific islands, including Fiji and Samoa. In New Zealand, it's commonly known as mamaku, a name from the Māori language. It grows in moist forests with a mild, humid climate. In the wild, these plants can grow very large — up to 15 to 20 meters tall.
What does it look like?
Cyathea medullaris has a straight, dark trunk, often almost black in color. That’s why it's also known in English as the black tree fern. Its fronds are bright green and can grow several meters long. They spread out gracefully from the top of the trunk, giving the plant a lush, almost tropical appearance. Like many ferns, young fronds slowly unroll from the center of the plant.
Care tips
Cyathea medullaris does have some specific needs in order to grow well. Here are a few key tips:
Water: Keep the soil consistently moist, but not soggy. Never let the roots dry out, especially in summer. It’s better to water more frequently in smaller amounts than to soak it all at once.
Humidity: This fern loves high humidity. Indoors, mist it regularly or use a humidifier
Light: Place it in a spot with bright, indirect light. Outdoors, it prefers partial shade.
Temperature: This fern is semi-hardy. Protect it from frost, especially when it's still young. An unheated greenhouse or sheltered outdoor spot is ideal.
Soil: Use rich, well-draining potting soil. Adding bark or perlite can help improve drainage and aeration.
Did you know...
The trunk isn’t a real tree trunk?
What looks like a trunk is actually a mass of old leaf bases and roots. It’s not made of wood like a regular tree.
Young fronds curl into a ‘koru’?
This spiral shape is called a koru in Māori. It symbolizes new life, growth, and harmony — and is a common design in New Zealand art and tattoos.
It’s a prehistoric species?
Tree ferns like the Cyathea medullaris have existed since the time of the dinosaurs, making them true living fossils.
Now available in size S
Excited to add one to your collection? The Cyathea medullaris is now available in size S in our webshop — perfect for a greenhouse, conservatory, or a sheltered spot in the garden.
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