How to Grow Tree Ferns
Although tree ferns are easy care in the right growing conditions you can run into a few problems especially during summer. The two main types grown in the garden are Dicksonia antarctica (Soft Tree Fern)and Cyathea australis (Rough Tree Fern) and both have similar c are requirements. Some of the main problems are under watering and exposure to hot sun. Using the wrong fertilizer to feed tree ferns can also cause trouble.
The fern pictured right has had a few problems, lack of water, 3 days over 35C and in a position where it gets to much sun to cope with neglect. However it does have some green growth left and can easily be brought back to life/
Often thought of as tough and indestructible they can in fact suffer badly during hot dry weather, especially those grown in the garden. Natural habitat is as an under story plant in forested areas, they are almost continually in dappled shade and the main source of water is that collected in the crowns, This water runs down the trunk and keeps it moist. They also absorb water from the ground, however not as much as you may think.
Tree ferns with sun burnt or dried foliage.
This is tree fern recovery 101.
In the garden it is easy to forget to water tree ferns, they look green and healthy, however if you do get a spell of hot weather, and they are in direct sun the foliage may be healthy one day, and after a day or two of high temperatures it can look burnt and dead.
If you have a tree fern that has been damaged by sun, a little quick action can bring it back to life.
- Firstly water well, the trunk and the soil, and do this every day until the weather cools down.
- Use some shade cloth to protect the crown from further burning and heat.
- Plant something that can give the fern more shade next year, give the fern extra care next hot season or transplant the fern to a cooler position.
General Watering of tree ferns.
If you can, water your tree ferns every week from the end of spring through to autumn with a bucket of cool water, pour it gently over the trunk so that it runs down and soaks the trunk. During hot spells water every second day. Of course if your ferns are tall, use a hose, just remember to water the trunk, preferably in the evening, if not early in the morning.
Fertilizing or ‘Feeding’ Tree Ferns
When we look at feeding tree ferns it is best to consider the natural process. We read a lot about using soluble fertilizers pored over the crown, not something we think is a good idea, and probably written by someone who has never grown them.
We have been growing tree ferns for 20 years in our garden, and have never used anything except organic fertilizers, and this has always been liquid seaweed fertilizers and only when transplanting. We do mulch them at the end of winter to retain moisture, but nearly all soluble fertilisers will have phosphorus in them, not something that tree ferns need.
You could try a little very weak liquid seaweed in early spring, however in good soil and if well mulched every year they should not need it. The mulch provides a cool moist root run and rots down to release nutrients. It also encourages worms, natures way of fertilizing.
If you are growing them in a container, then things change, a slow release organic fertilizer in the soil twice a year should do. And forget the banana skins, unless you want to encourage possums.
Pruning tree ferns
A little debate about pruning tree ferns , some tree ferns will drop old foliage others will seem to let it droop down to form a skirt.
This skirt actually serves a purpose, insulation from both heat and cold. It stops the trunk from drying out so much during hot spells and keeps it a little warmer during the extreme cold, however, unless you live in the UK or in the Alps this is not generally a problem and the skits can be pruned away.
HOWEVER, in warmer climates these dry ‘skirts’ can also be a fire hazard, and in our manicured gardens they can look a little unruly. Pruning old dead fronds from tree ferns will do nothing to encourage new growth it will just make your tree fern look better.