Tree ferns are truly beautiful plants that can bring prehistoric beauty to any indoor or outdoor space. They can live for many years if they get the right care. You can use this complete guide to pick out the right tree fern, plant it, water it, feed it, and fix common problems.
Overview of Tree Ferns
Tree ferns are very old plants that evolved with dinosaurs more than 200 million years ago. There are about 1000 species of tree ferns that live in tropical and subtropical areas around the world. The Australian tree fern (Cyathea cooperi) and the Tasmanian tree fern (Dicksonia antarctica) are the most popular types to keep indoors.
Tree ferns have a trunk covered in fibrous roots that support a crown of lacy fronds. They thrive in warm, humid environments similar to a rainforest understory. With the right growing conditions tree ferns can reach towering heights of 30-50 feet in their native habitats.
Choosing the Best Tree Fern
When selecting a tree fern, choose a variety suited to your climate The Tasmanian tree fern handles cooler temperatures down to 30°F better than the Australian tree fern. For tropical climates, the Australian tree fern grows larger and faster
Inspect the trunk and fronds for signs of pests, disease, or damage. Choose a plant with several unfurled fronds and a healthy root system on the trunk. Locally grown ferns are best acclimated to conditions.
Providing the Ideal Growing Conditions
Light
Tree ferns thrive in bright, indirect light similar to a rainforest understory. When grown indoors, place near an east or west window. Outdoors, choose a shady spot protected from intense midday sun.
Temperature
Keep tree ferns between 60-80°F. Move outdoor container plants indoors if temperatures drop below 50°F. Avoid cold drafts and heating vents for indoor plants.
Soil
Use a rich, acidic, humus-based potting mix. Add peat moss, sand, compost, and pine needles to your outdoor planting beds to make them better.
Water
Keep soil consistently moist but not soggy. Water when the top inch becomes dry. Mist the trunk and fronds frequently to increase humidity. Ensure proper drainage.
Humidity
High humidity around 60-80% is vital. Boost indoor humidity with misting, nearby plants, and a humidifier. Shelter outdoor plants from drying winds.
Fertilizer
Feed monthly with balanced organic fertilizer during spring and summer. Dilute any liquid fertilizer by half.
Caring for Tree Ferns Long-Term
Repotting
Repot rootbound ferns in early spring before growth resumes. Choose a pot 2-4 inches larger and refresh some soil.
Pruning
Remove dead or damaged fronds at the base using sterilized pruners. Wipe dust from leaves to improve air circulation.
Pest Control
Check regularly for scale, mealybugs, and mites. Isolate and treat using horticultural oils or insecticidal soaps.
Overwintering
In borderline climates, wrap trunks with horticultural fleece and fill crowns with straw. Move container plants indoors if colder than 30°F.
Troubleshooting Common Tree Fern Problems
Yellowing Fronds
This usually signals too much sun, under-watering, or insufficient humidity. Adjust conditions and prune damaged fronds.
Drooping Fronds
Indicates underwatering or low humidity. Increase watering frequency and misting.
Leaf Drop
Caused by cold drafts, pests, or transplant shock. Improve air circulation and acclimate new plants.
Slow Growth
Results from insufficient light, cool temps, rootbound plants, or underfeeding. Fertilize regularly and repot as needed.
Rotting Trunk
Due to overwatering or crown rot. Allow soil to partially dry before watering again. Avoid wetting the crown.
Final Tips for Tree Fern Success
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Gradually acclimate new plants to avoid transplant shock.
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Use rain or distilled water to prevent mineral buildup.
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Add pebbles below pots for drainage and aeration.
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Rotate plants periodically for even growth towards light.
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Monitor closely for pests in humid environments.
With proper care tailored to their preferences, tree ferns can thrive for decades as living fossils in any indoor jungle or tropical garden. Their gracefully arching fronds and prehistoric appeal make tree ferns well worth the minimal care required.
Where to grow tree ferns
Tree ferns can be grown in borders or containers and need a damp, shady, sheltered spot, out of direct sunlight and neutral to acid soil. They grow well in boggy conditions near water too.
Tree fern varieties to try
- Dicksonia antarctica – one of the hardier tree ferns. It looks good with other ferns and plants that can handle shade, or it can be used in an exotic planting scheme. It has been given the Award of Garden Merit by the Royal Horticultural Society of Great Britain.
- The Blechnum tabulare fern is evergreen and has big fronds that can grow up to 1 m long when they are fully grown. It’s not really a tree fern yet, but it will grow a trunk in the future.
- Dicksonia fibrosa is an evergreen tree fern that can grow up to 6 meters tall and has dark green fronds that can be up to 2 meters long.
- These evergreen tree ferns, Cyathea australis, are a little more delicate and may lose their fronds in colder places.
- Dicksonia youngiae is a tough tree fern that grows quickly and is native to Australia’s rainforests.
Five Mistakes to Avoid When Growing Tree Ferns – Dicksonia antarctica
FAQ
How often do you water a fern tree?
Keep the soil moist at all times. Australian tree ferns are not drought-tolerant and need weekly watering. In extremely dry weather conditions, their need for moisture and humidity is extremely important.
Should I cut the fronds off my tree fern?
In the winter the fronds will die down but do not cut them off until the following spring. Fold the fronds in before wrapping up your tree fern for winter.
Do you water tree ferns from the top or bottom?
It’s important to keep the trunk moist, as these aerial roots rely on that moisture to stay healthy. Here’s how I like to do it: Gently water the crown of the fern. Be careful not to drown the crown—just give it a nice, light soak so the plant gets moisture where it needs it most.
Do tree ferns like sun or shade?
Tree ferns thrive in a humid and shaded position. They will not tolerate temperatures below -5°C. Allow room for your tree fern to spread. Fronds on mature specimens may reach 2m (6ft) or more in length.