Transplanting Shrubs

Autumn is a good time for transplanting evergreen shrubs and small trees as the weather is cooling down and the plants won’t get as stressed as they would in the heat of summer.  The soil is warm, encouraging the roots to grow, and there is still some moisture in the air. 

There can be many reasons why a shrub or small tree may need to be moved.  It can be in a position that doesn’t suit it causing its growth to be stunted and it not to thrive.  It may be shading other plants, the lawn or areas of the home where full sun is needed or perhaps it just doesn’t suit the design of the garden.

Whilst autumn is the time for transplanting evergreens, deciduous trees and shrubs should not be moved until winter when they are dormant as moving them at other times of the year may cause their roots to rot.

Mature shrubs and trees can be very expensive to purchase from a garden centre so it is worth trying to save and transplant one that already exists in the garden.  But, it will take some time, plenty of thought and probably a few muscles from friends and family.

PREPARATION
Like most jobs around the house, transplanting is all about preparation.  Preparing the tree, deciding on a location and having the right tools ready will make the job a whole lot easier.

The success of transplanting often comes down to the health of the tree and shrub.  If it is already showing signs of stress, it may be the last straw for it to be moved and it might not survive.  Of course, if it is not surviving in its current spot, it is probably worth risking the move as chances are that it will be lost anyway.

However, to increase the success rate, start building up the plant’s strength several weeks ahead by applying weekly applications of seaweed extract over the leaves, trunk and soil around the roots.  Seaweed extract helps to thicken the cell walls of the plant so that it can withstand the stress of moving much better.  This can also be applied at transplanting and then weekly afterwards as it also encourages root growth.  It is not a nitrogen-rich fertiliser so will not cause an unwanted flush of leaves.

The new location of the shrub is a really important factor, not least because you won’t want to move it again if you make a bad choice.  Consider the requirements of the plant first and, if unsure, take a stem down to your local Better Pets and Gardens to ask for advice. Then, find an area of the garden that will suit the plant as well as the need of the family.  Consider the direction of the sun at all times of the day, including the shadow that the newly moved shrub or tree itself will cast on other plants in the garden.  Also make sure that the amount of water and the soil requirements of the new plant suites the others in that zone so that watering and fertilising is easy to carry out.

Prepare the new hole early.  Don’t add fertilisers to the hole as the increased supply of nitrogen from this might burn the new roots and will encourage new leaf growth which will stress the plant.  The aim is to get the roots of the tree or shrub to establish before new leaves are formed.  Add a few shovel loads of sheep manure to the hole instead as this is low in nitrogen.  Then, once the plant is in the hole, an application of slow release fertiliser can be sprinkled over the top.

Make the hole twice as wide as the root ball is expected to be.  This is hard to judge at this stage but it is important to break up the area around where the roots end up so that they can grow easily into it.  Keep the base of the hole solid however to give a good foundation to the root ball and prevent it sinking.

It’s worth investing in a bottle of spray-on leaf polymer which is available at Better Pets and Gardens.  This innovative product puts a protective film over the leaves and stretches as they grow, lasting up to 90 days.  It protects the plant from water loss, reduces water usage by up to 50% and increases the survival of plants being transplanted.  This means that even though the roots have been cut and aren’t taking up as much water, the plant itself won’t be losing much either and so should cope until the roots start to do their job again.  This product comes in a trigger pack and can be applied several hours before the move.

MAKING THE MOVE
Prune the tree of water shoots and then dig a ditch around the tree and use this to give the roots a good soak.  Make sure that the water has gotten right down into the soil as this will help prevent transplant shock.

When the soil is saturated, the main roots can be exposed so that they can be cut.  This is where the friends with muscles and sharpened shovels come in as this can be hard work.  Don’t cut the roots too close to the trunk but the size of the final root ball will depend on the species being moved.  You will soon be able to work out where the bulk of it is.  Once the side roots have been cut, use the shovel to slide in underneath to cut any deeper roots.  The idea is to keep as much of the root ball intact as possible but if the soil is sandy, this will soon fall off in the moving process anyway.

Before removing the shrub or tree from the hole, mark the side of it that faces north.  This will help you orient the shrub so that it faces a similar direction later to prevent sunburn from the harsh northern sun on the softer, south facing leaves or trunk.

Once the root ball is separated from the soil, move the tree or shrub onto a tarp to make transporting easier.  Use the tarp to drag the tree to the new hole and gently ease it in.  Spend some time positioning it carefully making sure that it is facing the correct way and that the trunk is straight.  If you get it wrong at this stage there will not be an opportunity to correct it later.  Aim to have the top of the root ball level with the top of the soil in the new position.

Shovel the excavated soil back into the hole, gently tamping it down and watering it as you go.  This will eliminate air pockets which could cause the plant to shift later on.  Mound up more soil in a ring around the newly planted tree as this will act like a basin, catching the water and ensuring that it goes to the recovering root ball.

AFTER CARE
Mulch is essential for a newly transplanted tree.  Spread a 10cm layer both inside and outside the tree, making sure that it doesn’t touch the trunk and then add that application of controlled release fertiliser.  Applying a soil wetting agent is also a great idea at this stage to ensure that the water gets down to the roots through our hydrophobic WA soil.

Then, water, water and more water until the shrub or tree is established adding some seaweed extract to the bucket every week or so.  After four to six weeks the amount of water provided can be reduced but if the roots are allowed to dry out, the plant will die and all of your hard work will be lost.

Transplanting a tree or shrub is not always easy work but as hard as it is on you, it is probably even harder on the plant.  But, once it recovers from the transplant shock, it should offer many more years of pleasure which certainly makes all of your efforts worthwhile.