Tree ferns are among the most magnificent and resilient of all plant species and posses an architectural quality almost unique in nature. Unfortunately it is the very fact of its uniqueness that causes concern when it comes to looking after them. Why, well it’s because - when purchased - tree ferns generally come without a root system, and look more like a detached elephant leg than anything else.


Luckily, watering tree ferns is very simple; it is just a case of mimicking how they would receive water in their native habitat. Tree ferns live below the tree canopy along the floor of temperate rain forests but as well as absorbing ground water through their roots they can also collect water from their leaves which drains into the crown and further down into the trunk. Their specialised fibrous trunks can also collect water either as rain falling onto it or from water droplets from mist and fog.

In the garden situation you would use either a hose or watering can fitted with a rose, watering the entire plant from top to bottom. While your tree fern may be bought without roots, once potted on these will be produced during the growing season.

If your tree fern is positioned in full sun it is likely to need watering most days, especially during the summer. If it is growing in the shade or semi-shade then you should be able to get away with watering every two to three days. Once the cooler temperatures of autumn arrive watering can be dropped off to perhaps once a week but you still do not want the truck or the crown to dry out. It is only over the winter period that the crown should just be kept on the damp side, but it may also require protection to stop the crown from fully freezing and damaging next seasons new growth.

If you have purchased your tree fern as just a cut trunk it is worth letting it soak in a bath of water for an hour or so before planting.


Feeding a tree fern is relatively easily because - like most other plants - they are able to retrieve nutrients from the soil using its root system. However, they also have a secondary formation of roots within the trunk which reaches close to the top of the crown. This enables tree ferns to also feed on accumulated debris, bird and animal droppings that are washed into the crown by way of their specialist fronds during rainfall.

Feeding from the crown will be important when you first purchase a tree fern as they will generally come cut at the base and therefore without a root system. At this time feeding is important as the tree fern will be stressed and will have little energy reserves with which to produce new leaves and an essential, replacement root system.

It is good practice to soak a new, cut tree fern in a bath of water for an hour or so before planting, but is also well worth adding a half to quarter dose of soluble plant feed in with the water – especially if bought during the spring and summer months. To prevent fertilizer wastage only apply soluble fertilizers via the crown but as the plant becomes established it will do well with a regular mulch at the base. Continue to regularly water the trunk and crown until the first frond unfurls, at which point a half dose of soluble plant fertilizer can be applied once a week. As soon as the tree fern starts producing new fronds on a regular basis it can then be fed the recommended dose of plant fertiliser once or twice a week.

When trees ferns are established they can utilise a surprisingly large amount of nutrition, and in a good year are able to produce a second ring of fronds on top of the first. If you intend heavily feeding your tree ferns then it will be important to also water them regularly – at least twice a day morning and evening – so that they do not suffer with root burn.

Once the growing season moves into the autumn period it’s best to end feeding to allow the existing fronds to harden up for the winter. As soon as the first frond opens in the spring feeding can once again commence at the half dose concentration.


When it comes to tree ferns you should always lean to the safe side. Consider the worse weather that the winter climate is likely to throw at you, and protect your plant against that. You can do this in one of two ways.

1. Protect you fern for the entire winter period or

2. Only protect your fern when temperatures get close to the limits that it can survive at.
Which parts of the tree fern will need protecting?

Although it’s the fronds that are most susceptible to the cold, they are also in fact the most expendable. It is the crown of the trunk that is the most important part as this is where the meristems exist which will produce the following years growth. Next in line is the trunk because this protects the thick, boot-strap like roots which – if the crown dies – may be able to produce new meristematic tissue from dormant buds which will in turn produce new fronds – but don’t hold your breath. Coming in third in the hierarchy of importance is the thick, fibrous root system at the base of the plants. If the root system dies - but the crown and the thick roots within the truck survive - there is nothing to worry about as these will re-grow over the following season. I would still protect them just to be on the safe side as less hardy species - such as Dicksonia squarrosa - can form multiple crowns and will grow back from the base if the crown is cold damaged – but only if it is mature enough.

Methods of protection

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In their native habitat the crowns of tree ferns will normally be protected by leaf litter that has fallen down from the tree canopy above. You can easily mimic this with leaves collected from around the garden, and this will work quite effectively down to temperatures of between 1 or 2 degrees below freezing.

However the best method is to plant the tree fern in the ground but with the root-ball still contained in some type of pot. That way it can be lifted before the cold depths of winter arrive without disturbing the root-ball. Remember that - come the spring - the tree fern will need to be hardened off again. Unfortunately this will be dependent on the size and weight of the tree fern, and whether suitable over-wintering space is available, otherwise the yearly lifting of your tree fern may not be a viable option.

The most popular method used for protecting tree ferns is to surround the entire plant – excluding the fronds as these will grow back – with a simple structure filled with a natural insulation. The structure can be made of anything that is sturdy enough such as wood, plastic tubing or a firm wire mesh. This can be covered with clear polyethylene sheeting, bubble wrap, loft insulation – again, use whatever is suitably appropriate and close to hand. This in itself may be perfectly adequate, but for extra protection you can back fill the structure with a good layer of straw or woollen fleece. I would recommend putting on some kind of a water-proof lid above the structure but make sure there is a good air gap between the top and the sides to prevent the build up of condensation on sunny days. At all times the crown must be kept moist especially if the weather picks up, but try not to have it wet during the cold spells as freezing will damage the crown.

As an additional precaution for the cautious, you can build up a mound of soil around the base of the trunk to help protect the root system and the lower body of the trunk from the cold.
For more information click onto:
Bomarea caldasii
Cold Hardy Plants with Giant Leaves

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