Kermadec tree fern Plant Care
Alsophila kermadecensis (Oliver) R.M.Tryon
Updated · Sources · How we source care data
Alsophila kermadecensis, synonym Cyathea kermadecensis, is a species of tree fern endemic to Raoul Island in the Kermadec Islands, where it is locally common in damp, and sometimes drier, forest and scrub. The trunk of this plant is erect, slender and up to 20 m tall.
Every 7–14 days
Bright indirect to low light
60–80°F
60–80%
At a glance
How do you care for Kermadec tree fern?
Water Kermadec tree fern every 7–14 days, letting the top layer of soil dry out between waterings, and give it bright indirect to low light. It prefers temperatures of 60–80°F (16–27°C) and 60–80% humidity. Fertilize it every 6 months during the growing season.
What Is the Kermadec tree fern?
Kermadec tree fern (Alsophila kermadecensis) belongs to the Cyatheaceae family within the Alsophila genus. Kermadec tree fern is native to Raoul Island in the Kermadec Islands.
Kermadec tree fern displays a large, tree-like fern growth habit, reaching up to 10 ft tall with a spread of approximately 5 ft. Kermadec tree fern produces non-flowering.
Leaf size: approximately 36 inches.
How Often Should You Water a Kermadec tree fern?
Alsophila kermadecensis requires watering every 7–14 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 7–14 days
Let soil partially dry between waterings
What Light Does the Kermadec tree fern Need?
Kermadec tree fern thrives in bright indirect to low light. Avoid placing Kermadec tree fern in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Bright indirect to low light
What Temperature and Humidity Does the Kermadec tree fern Prefer?
Alsophila kermadecensis grows best at temperatures of 60–80°F. Kermadec tree fern prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
60–80°F
Humidity
60–80%
What Soil Mix Works Best for a Kermadec tree fern?
Rich, well-draining soil with high organic content. Good drainage is essential for Kermadec tree fern to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Kermadec tree fern?
Feed Kermadec tree fern every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Kermadec tree fern?
Repot every 2-3 years. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Kermadec tree fern?
Kermadec tree fern can be propagated through spores. Similar propagation techniques also apply to tree fern plant care, which shares the same genus.
Is the Kermadec tree fern Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Kermadec tree fern, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Kermadec tree fern?
Kermadec tree fern is susceptible to spider mites, scale insects. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Kermadec tree fern Need?
Kermadec tree fern grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Kermadec tree fern is native to Raoul Island in the Kermadec Islands. In cooler regions, grow Kermadec tree fern as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 13a
Keep exploring plants
Kermadec tree fern is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Alsophila genus — compare its care with other Alsophila species on PlantoScan.
Alsophila is part of the Cyatheaceae plant family — browse all Cyatheaceae genera and species.
Kermadec tree fern copes with lower light than most plants — browse the full list of low-light plants.
More Alsophila Species
Other Alsophila species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Alsophila kermadecensis (Oliver) R.M.Tryon, family Cyatheaceae (first published in Contr. Gray Herb. 200: 37 (1970)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Kermadec tree fern, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 13a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
Identify Plants Like the
Kermadec tree fern Instantly
Scan any plant with your phone camera and get instant ID, care tips, water and fertilizer reminders, and health checks — all in one app.
Free
to download
iOS & Android
platforms
Light & dark
mode
100,000+
species