Photo: Poyt448 Peter WoodardCC0via Wikimedia Commons
St Helena Tree Fern Plant Care
Sphaeropteris excelsa (R.Br. ex Endl.) R.M.Tryon
Updated · Sources · How we source care data
Native to New Guinea, this plant's most distinctive feature is its large, glossy, dark green fronds that can grow up to 10 feet long. Its elegant and striking appearance makes it highly sought after by plant collectors looking to add a touch of tropical beauty to their collection.
Every 7–14 days
Filtered sunlight or partial shade
60–75°F
60–80%
At a glance
How do you care for St Helena Tree Fern?
Water St Helena Tree Fern every 7–14 days, letting the top layer of soil dry out between waterings, and give it filtered sunlight or partial shade. It prefers temperatures of 60–75°F (16–24°C) and 60–80% humidity. Fertilize it every 6 months during the growing season.
Where Is the St Helena Tree Fern Native To?
What Is the St Helena Tree Fern?
St Helena Tree Fern (Sphaeropteris excelsa) belongs to the Cyatheaceae family within the Sphaeropteris genus. St Helena Tree Fern is native to Norfolk Island, in the Pacific Ocean near Australia and New Zealand. St Helena Tree Fern is also known as Alsophila excelsa, Cyathea brownii.
St Helena Tree Fern displays a large, spreading fern growth habit, reaching up to 5 ft tall with a spread of approximately 4 ft. St Helena Tree Fern produces non-flowering.
Leaf size: approximately 24 inches.
How Often Should You Water a St Helena Tree Fern?
Sphaeropteris excelsa 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 St Helena Tree Fern Need?
St Helena Tree Fern thrives in filtered sunlight or partial shade. Avoid placing St Helena Tree Fern in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Filtered sunlight or partial shade
What Temperature and Humidity Does the St Helena Tree Fern Prefer?
Sphaeropteris excelsa grows best at temperatures of 60–75°F. St Helena Tree Fern prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
60–75°F
Humidity
60–80%
What Soil Mix Works Best for a St Helena Tree Fern?
Well-draining, rich, acidic soil with high organic content. Good drainage is essential for St Helena Tree Fern to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a St Helena Tree Fern?
Feed St Helena 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 St Helena Tree Fern?
Repot every 2-3 years in spring. 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 St Helena Tree Fern?
St Helena Tree Fern can be propagated through spores, division of rhizomes. Similar propagation techniques also apply to cooper's tree fern plant care, which shares the same genus.
Is the St Helena Tree Fern Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list St Helena 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 St Helena Tree Fern?
St Helena 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 St Helena Tree Fern Need?
St Helena Tree Fern grows outdoors in USDA Zone 9b – 11b. It survives winters down to planting zone 9b. St Helena Tree Fern is native to Norfolk Island, in the Pacific Ocean near Australia and New Zealand. In cooler regions, grow St Helena Tree Fern as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 9b – 11b
Keep exploring plants
St Helena 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 Sphaeropteris genus — compare its care with other Sphaeropteris species on PlantoScan.
Sphaeropteris is part of the Cyatheaceae plant family — browse all Cyatheaceae genera and species.
St Helena Tree Fern thrives in bright light and direct sun — see other bright-light plants.
More Sphaeropteris Species
Other Sphaeropteris species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Sphaeropteris excelsa (R.Br. ex Endl.) R.M.Tryon, family Cyatheaceae (first published in Contr. Gray Herb. 200: 24 (1970)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list St Helena 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.
- Photo: Poyt448 Peter Woodard, CC0, Wikimedia Commons — original.
- Hardiness zone: USDA Zone 9b – 11b, estimated from the plant's typical growing conditions.
- 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.
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