Plant Doctor Archive

Shifting tree ferns

I have to move two pongas that are about 7-8 ft tall and growing too close to the house. There are five others that are stunted and look to be in a bad way, that also have to be moved. I would like to replant to a more open location. What care do I need when I dig them up and have you any tips with replanting?

ALL tree ferns transplant successfully without much fuss, especially at this time of year, and you don't have to take a large root system.

To make them easier to handle, and to reduce transpiration until new roots have formed, cut off most of the fronds before you dig them up. Push a sharp spade into the soil to its full depth about 20-30cm out from the base of the trunk to cut the roots. You should then be able to lever the tree ferns over to one side and chop through their basal roots.

Take them to their new position and replant at the same depth as before. If there's any risk of them being exposed to wind, you should stake the tallest ones for at least a year until they've established a strong root system. A good way is to have three stakes at equal distances around the trunk about 50cm out from it then a tie from each stake to the trunk. Ideally, place the ties about one third of the way up the trunk. This way it's held firm regardless of which direction the wind is coming from.

Water them well, apply a layer of mulch and then in summer give them a good watering once or twice a week until they're growing well. But don't be fooled by the first new fronds that develop into thinking you can stop watering - transplanted tree ferns often send out new fronds before they've grown new roots and if the soil dries out excessively they may wilt and die.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.