Planting and Transplanting
The first thing to consider before planting or transplanting your tree fern is where you are going to plant it. The conditions which Dicksonia antarctica tree ferns do best in are sheltered spots with filtered sunlight. Although the Tasmanian tree fern will tolerate other conditions it will thrive in a still damp corner out of constant draughts. Finding this type of position will also keep the humidity higher around the plant and cut down on the amount of watering required. It is best to plant tree ferns in the spring when the soil has warmed up. I would avoid any plantings in winter as the ground maybe too cold and wet.
Once you have chosen a spot the next thing to prepare is the soil.
Let’s consider the natural habitat in Australia where this tree fern grows, under the canopy of trees. In this environment you can envisage a free draining nutrient rich soil. This is what we want to try and recreate. To do this I usually start with ericaceous compost and add in finely mulched bark chippings to open the soil up. I then add to this a good amount of semi broken down leaf mulch. I make sure the ingredients are well mixed and put them in a pile next to where I am going to plant.
The next thing is to dig your hole. If you have a plant with a developed root system dig the hole twice as big as the roots will fill. If you have a trunk which has been cut top and bottom you want to plant as little as you possibly can in the ground whilst making sure the plant will be stable. Otherwise you have paid for something you are going to bury! When planting a trunk I normally make a hole 10cm bigger than the diameter of the trunk and about 20cm deeper than I will want the plant to finally rest. This should allow enough of your soil around the plant without losing too much stability. I then fill the hole with my soil and firm it down so the plant doesn’t sink but not so much as to stop the drainage. Next place the trunk or rooted plant into the whole and fill in with soil and make sure you have firmed the soil in well. If you feel the trunk needs extra support you can stake the plant until its roots have established.
After you have finished the planting put a layer of coarse bark chippings or leaf mulch around the trunk. You can put fish, blood and bone around the base as well to give your trunk an extra kick start.
If you live in an area with very heavy clay soils you will need to pay extra attention to the soil around your tree fern ensuring good drainage and a neutral to acid soil ph. One want of achieving this may be to line the whole with pond liner and add drainage at the bottom or you maybe better of buying a large container 50+ litres and sinking this into the ground. If preferred Dicksonia antarctica tree ferns can be grown as pot specimens. Again, plant as shallow as possible, but remember when picking up the pot that the log will fall out if not held upright. After about 1 year, roots should appear from the bottom of the pot. The plant can then be re-potted into a larger container.
I would ensure that that the trunk is well watered in the days before and just after planting. If planting a small trunk it will not harm it to be completely soaked or submerged in rain water.
Do not be alarmed if the first few flushes of new fronds are stunted or shorter it will take a little time for the plant to re-establish its nutrient supply. It may never get back to its previous best but if given the correct conditions and a lot of water it should still make a fantastic specimen.