Mamaku (Sphaeropteris medullaris)
Care, watering, light and tips for Mamaku on Floravia.
Quick facts
- Family: Cyatheaceae
- Difficulty: Demanding
- Watering: every 3 days
- Light: Partial shade
- Temperature: 10–30 °C
About Mamaku
Sphaeropteris medullaris, also known as the sago fern or black tree fern, is an imposing tree fern capable of reaching significant sizes, featuring arching fronds and a stout trunk covered in black scales. Its majestic presence makes it a spectacular focal point in tropical and subtropical gardens, or in large containers in greenhouses and sheltered patios. Young fronds, known as 'koru,' unfurl gracefully, adding unique visual interest as they mature.
Native range
New Zealand and some South Pacific islands, such as the Chatham Islands and Norfolk Island
Care tips
This tree fern thrives in partial to full shade, protected from direct sun which can scorch its fronds; it requires high ambient humidity and consistently moist but well-drained soil. Water generously, especially in warm climates, and never allow the substrate to dry out completely, but avoid waterlogging. A rich, organic, and well-draining substrate is ideal. A common mistake is underestimating its need for humidity and wind protection, which can lead to dry and damaged fronds.
How to save a dying Mamaku
- Warning signs
- Dry, brown or yellowing fronds, especially new ones. Soft or wet stem base.
- First aid
- Increase humidity (mist, pebble tray). Check soil: if dry, water thoroughly; if waterlogged, remove excess and improve drainage. Protect from direct sun.
- What kills it
- Constant low humidity and direct sun, causing rapid drying. Also prolonged waterlogging leading to root rot.
- Can it be saved?
- Yes, if the main trunk isn't completely soft or rotted. Act quickly to adjust humidity and watering.