Life or death can happen very quickly in the garden.
I know it’s nothing like being in the ‘Death Zone’ of Mount Everest or anything but this Summer in Melbourne has been absolutely hazardous for plants.
As part of reclaiming our front garden this Summer (see Form vs Function in a Modernist Garden) we wanted to recycle and reuse materials and transplant plants wherever we could. While this would obviously help our project budget, as landscape architects we feel a responsibility to be as sustainable as possible within our own home and garden.
So after reusing bricks, pavers and gravel where we could, then buying recycled bluestone blocks from somebody’s old driveway, we were keen to keep and transplant as many existing plants as possible.
Transplanting Australian Natives
Generally I would say that transplanting plants is not a good idea once they are in the ground. These plants have had to deal with being taken from pot to pot as they are cultivated, then moved around nurseries, before being thrown into the back of a car/truck/trailer and then finally planted into soil that is entirely different to the lovely growing medium they are used to.
So once they are in the ground, I think it is best to let them be and establish in their new home. However, there comes a time when a plant ‘needs’ to move, so here are some key points to keep in mind:
There are some natives that can be transplanted pretty easily and some that absolutely hate it. You are generally pretty safe with hardy tuberous rooted plants such as Anigozanthos (Kangaroo Paw) and running plants such as Dianella (Flax Lily), however you are really playing with fire if you want to move a Xanthorrhoea (Grass tree)!
In general Banksia, Callistemon (Bottle Brush) and Grevillea species don’t like being transplanted while Eucalyptus, Melaleuca (Paperbark) and most other native trees and shrubs can be transplanted successfully (with care).
Time of Year
The best time of year to transplant is during Spring or Autumn (unlike our recent project) so that the plants are not dealing with extremes of heat or cold while they are being put through a move.
No matter what time of year or species you are dealing with, the size of the root ball that you dig out with the plant is VERY important. Technically for a tree you should take a root ball of diameter 10 times that of the trunk (J Pike 2002), however that is not always practical based on the plant’s location.
What is important is that you don’t sever large significant roots, so we generally dig carefully around the base of the tree to determine where the important roots are going and them dig them out with as much soil as possible.
For shrubs and groundcovers make sure you take a good amount of soil and roots with the plant relative to its size.
Make sure the plant is going to a location that suits it for size, sun exposure, drainage, etc and then make sure you dig a large enough hole to take the root ball. It is better to dig a bigger hole and then back fill with soil around the newly placed plant. You should water in the hole before planting (especially if transplanting in Summer) and stake any trees or shrubs that need it.
Water & Mulch
Plants should be given a good surrounding of mulch to help maintain soil moisture, soil temperatures and prevent weeds. Make sure that mulch does not sit up against the trunk or stem of the plant as this can lead to rotting. A good method is to create a bowl of mulch around the stem of the plant so that water pools in the area before being absorbed.
Give each plant a good water in. To encourage plants to be more self sufficient and drought tolerant it is better to give less frequent, longer waters. During establishment I have been watering every second day (although it has been more often during the heatwave) and given each plant a concentrated drink at the base of their trunk or stem (for about 20 seconds each).
So how did our plants go?
We have had varied results with our transplants.
As mentioned above, Grass-trees do not transplant well and we ‘needed’ to move one of ours. I hated the thought of losing such a beautiful plant and my wife Amy did some research to see how it could be done. The trick with Grass-trees is that they can get too wet, so I have been watering it a bit, but not so much that it will get water-logged. Our soil is very, very sandy so it should be draining well and so far this guy is doing well!
We also dug out a pretty established Bottle Tree (Brachychiton rupestris) out of the mound and discovered it to have an amazing tap root. This was quite a stressful transplant, as we were trying not to break these roots while replanting and so far this tree is doing well in its new location (as long as I don’t over water it).
Beneath the mess of our mound we found a Monstera deliciosa which is a classic mid-century plant. We put this in a nice sheltered location and while it copped a bit of a battering during the heatwave, it has put on new growth and appears to have survived.
Some scattered Dianellas and Bromelliads (not native but still look good) are doing well and will create some good filler plantings around our new plants.
Early on in the project I dug out some Dianellas, Ficinias and Lomandras and planted them along our driveway mound. Unfortunately this was a rushed job and I didn’t mulch, so with the very sandy soil any water just ran straight off the mound and these plants have struggled.
We also planted a groundcover Grevillea to the top of the mound and with sadness I noticed this has not survived.
Two Leucodendron were planted in front of our dining room and while I thought they were doing ok, they have also succumbed to the pressure of the move.
So is it survival of the fittest?
When transplanting there are many variables to the plant’s survival. Some species just don’t like it, the weather might work against you and the steps taken to transplant are important.
But sometimes you could do all the right things for the right plant at the right time of year, and for an unknown reason it dies.
That’s just bad luck.
J Pike, 2002, “Tree Moving” University of Melbourne – Plants and Planting Design Lcture Notes