Soft tree fern
Alsophila smithii · Cyatheaceae
The gardener's calendar
Ideal time to plant soft tree fern: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Common name
- Alsophila Tree Fern
- Family
- Cyatheaceae
- Plant type
- Tree fern
- Foliage
- Evergreen, divided and elegant fronds
- Mature size
- 2 to 4 m tall
- Growth
- Slow to moderate
- Hardiness
- Frost-tender (min. 10–12 °C)
- Origin
- Tropical and subtropical regions of Australia and the Pacific
Care
Light and exposure
Position Alsophila smithii in partial shade or under filtered, indirect light. Indoors, place it near a window without direct rays that could scorch its delicate fronds. It tolerates shaded areas but grows more slowly there.
Watering
Keep the substrate consistently moist without waterlogging it. Water regularly, especially during the growing season and in warm weather. Prefer soft water or rainwater, and mist the fronds to recreate the tropical humidity it naturally appreciates.
Substrate and soil
Use a rich, well-draining and aerated mix: leaf mould, peat, bark and perlite. Slightly acidic to neutral pH works perfectly. Ensure excellent drainage to prevent root rot, despite frequent watering.
Fertilising
Apply a balanced, diluted fertiliser monthly during the growing season (spring–summer). Choose a formulation low in nitrogen to avoid unbalanced growth. Stop fertilising in winter.
Pruning and cleaning
Remove only dead, damaged or yellowed fronds by cutting them at the base of the petiole. Regularly clean the fronds with a damp cloth to remove dust and promote good photosynthesis. Avoid leaf-shine products that clog the stomata.
Pests and diseases
Watch for mealybugs, spider mites and whiteflies, especially in dry air. Increase humidity and inspect fronds regularly. Fungal problems occur mainly if water stagnates; ensure good air circulation around the foliage.
Did you know?
Alsophila smithii and its tree fern cousins are among the oldest land plants: their ancestors already existed in the Carboniferous period, over 300 million years ago, long before flowers appeared. Their characteristic trunk is not true wood, but an interwoven mass of aerial roots and persistent frond bases, making them surprisingly lightweight despite their imposing stature.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
- Sphaeropteris tomentosissimaSphaeropteris tomentosissima
- Rough tree fernAlsophila australis
- Cyathea planadaeCyathea planadae
- Alsophila dealbataAlsophila dealbata
- Pedunculate oakQuercus robur
- CamelliaCamellia japonica
Tips generated and checked by Viridia — adapt them to your local climate.