HOW TO GROW TREE FERNS |The Garden of Eaden

How to grow tree ferns

Tree ferns are among the most ornamental all plant species and possess exceptional architectural quality. Unfortunately, when you purchase a tree ferns it is usually just a trunk in a pot and new stock will generally be without a root system. However, get the cultivation right and you will end up with an impressive and vigorous specimen plant.

Native tree fern woodland

Native to the acid woodlands of south-east Australia, the closer you can mimic their natural habitat the more impressive your specimen will be.

They thrive in a sheltered, humid and shaded position, so for the best start they should be planted in humus-rich, neutral to slightly acid soil. Extremely slow growing, these desirable plants only increase their trunk height by about 2.5 cm (1 inch) a year. Therefore, if you want a plant for immediate effect, you should choose a fern with a length of trunk that suits your planting scheme. If you buy containerized ferns in leaf, plant at the same level as they were in the container. Frond-less lengths of trunk are also available. Plant just enough of the trunk to ensure the plant remains stable. After planting frond-less tree ferns water every day until the foliage starts to emerge.

How to water tree ferns

Sawn tree fern trunks

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 specialized 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.

Tree ferns

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 season's 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.

HOW TO FEED TREE FERNS

Tree fern crown

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.

Tree fern forest

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 fertilize once or twice a week.

When trees ferns are established they can utilize 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.