Growing a tree fern in a pot

What type of pot to choose?

Choose a pot for your tree fern that is approximately twice the size of the root ball. To give you an idea, if your tree fern is 1 m tall, opt for a pot that is at least 40 to 50 cm in all dimensions. We recommend choosing a plastic pot rather than a terracotta one, as it is lighter and more economical, and it will retain moisture better, preventing the substrate from drying out too quickly. Also, ensure that the pot has drainage holes.

What substrate to use?

Tree ferns prefer light, cool, well-draining substrates that are slightly acidophilous but rich in humus. We recommend creating a mixture consisting of potting soil and garden soil (if it is not too calcareous), to which you can add heather soil, a bit of sphagnum, and coarse sand.

Two young tree ferns grown in pots: Cyathea australis and Cyathea lunulata (photos: sanxiaodevea)

Which species to choose?

Dicksonia antarctica - Tree Fern

Dicksonia antarctica is a stunning tree fern that adapts well to pot cultivation. It is probably the most commonly grown tree fern and one of the hardiest: it can withstand temperatures as low as -7 °C (even down to -10 °C with protection). Its thick, voluminous stipe is topped by lush foliage.

• Height at maturity 6 m

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Dicksonia squarrosa - Tree Fern

Dicksonia squarrosa forms a slender stipe and is more modest in size compared to Dicksonia antarctica. It is also slightly less hardy.

• Height at maturity 3 m

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Cyathea cooperi - Australian Tree Fern

Native to Eastern Australia, this tree fern is one of the most commonly cultivated. It displays large light green fronds supported by an upright stipe.

• Height at maturity 5,50 m

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Cyathea australis - Australian Tree Fern

Cyathea australis has a slender black stipe and boasts very beautiful lush foliage. It can tolerate temperatures down to -10 / -12 °C, but is somewhat more delicate to grow than Cyathea cooperi.

• Height at maturity 6 m

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When and how to plant a tree fern in a pot?

We recommend planting your tree fern at the beginning of spring.

1. Take a large pot with drainage holes.
2. Place a drainage layer at the bottom of the pot, made of clay balls, gravel, or broken pot pieces, for example.
3. Add a portion of the substrate, up to about one third of the height of the pot.
4. Gently remove the fern from its original pot, then place it in the new one, right in the centre. Ensure that the stipe is upright.
5. Fill in by adding substrate.
6. Lightly compact all around.
7. Water generously the substrate and the stipe.

You can add a layer of organic mulch on the surface to keep the substrate fresh for longer.

Then, place the tree fern in partial shade, in a sheltered spot from the wind. You can also position it in a greenhouse or conservatory.

Tree ferns are sometimes sold as sections of stipe, without roots or leaves. In this case, it should be potted by burying the stipe a quarter of the way, and staked to keep it upright. The stipe must not dry out until the fern has developed new roots.

To plant a tree fern in a pot, start by placing a drainage layer at the bottom of the pot, then add the substrate and plant the fern.

How to care for it?

Watering

Tree ferns are particularly sensitive to drought: they thrive in humid environments, and it is important that their stipe does not dry out. We recommend regularly providing water directly to the top of the stipe, at the centre of the crown of fronds. Preferably use rainwater, as tap water may be too hard for them. They will also appreciate regular misting of the foliage with a spray bottle.

Feel free to add a layer of organic mulch on the surface (such as fallen leaves, straw, or pine bark) to help keep the substrate cool for longer.

You can also apply liquid fertiliser, diluted in the watering water, at a rate of once a month from spring to autumn. However, be careful to dilute it twice as much as the product’s recommendations.

→ Read also How to Water a Tree Fern Properly

Wintering

In autumn, place the pot in a frost-free conservatory or greenhouse that is minimally heated. Ideally, the temperature should be between 2 and 10 °C. You can bring it back outside in spring.

Repotting

We recommend repotting your tree fern every year, choosing a pot that is slightly larger than the previous one to accommodate its growth.