Q When is the best time of year to move trees and shrubs?

A Generally, autumn is the best time for moving plants. However, most evergreen shrubs and trees should only be moved when their roots are active; early October or March is best. If you move them late in autumn and the following winter is very cold, dry, or both, then evergreens will be in danger of desiccation and water stress. This is because they retain almost all of their foliage.

If evergreens are transplanted during the milder, moister times of the year, then the roots are capable of starting to grow again straight away, while the tops are not in active growth.

Deciduous trees and shrubs are less fussy than evergreens. They can be moved any time between November and March.

Caption: A plastic bucket is a useful way of carrying smaller shrubs to their new home

Q When shouldn’t I move my plants?

A Do not move plants if the ground is frozen. Also, if your soil is heavy or gets waterlogged in winter, wait until spring to move them.

Q My shrub is too big. Should it be pruned or moved?

A If your plant is taking up a valuable sunny spot, but would do just as well in a more shaded position, move it. You can use the new space for a different, and perhaps more interesting, shrub.

Q How likely is it that the move will be a success?

A Moving trees and shrubs is not as risky a business as you may think. A Which? Gardening survey found that 70% of readers' shrubs flourished after moving, while only 10% did poorly. More than four out of five small trees and conifers also did well.

Q How do I know how far the roots of the plant I’m moving will spread?

A Tree roots generally spread to about a quarter of their height. The roots of shrubs are usually about the same width as the spread of the older, thicker branches.

Q How deep will the roots be?

A This depends partly on the kind of soil you have. Roots grow deepest in sandy soil; dig down to about 60cm to get beneath them. Dig to 30cm in clay and 45cm in loam. Plants on thin, chalky soils won’t have many roots growing below 20cm. Bear in mind that a 45cm-deep rootball measuring 90cm across could weigh close to a tonne, so recruit some help!

Q How many roots should I try to save in the move?

A All plants absorb water only through their extremely fine, hair-like roots. When moving a plant, don’t worry about cutting through some woody roots, but save as many of the delicate, fibrous ones as you can. Any disturbance will break them, so be as gentle as possible.

Q Do I need a stake?

A Tall trees and large evergreens may need to be staked when replanted in a new position. The Forestry Commission advises one short stake, no more than a third the overall height of the tree or shrub.

A short stake is enough to hold the roots firm, but allows the tree to flex in the wind and gain strength in the appropriate part of the trunk. A tree’s stem only thickens in response to the natural bending that occurs as it moves in the wind. If it is held rigid, by a long stake for example, it will not get the stimulus to thicken. Trees with stakes that are too tall are often narrower near the ground than they are above the top tie. If the stake breaks or is removed from trees like this, even after several years, the tree may fall over.

The stake should be put in place before the tree itself. After planting, tie the tree to the top of the stake and use a spacer to prevent the tree from rubbing against it. You should check regularly that the tie is not tight or restricting growth. Stakes should only be needed for two or three seasons.

Q What about aftercare?

A Keep newly moved plants very well watered for the first couple of months after moving. If the roots or the soil around the plant become dry then it will lose water, even if it has no leaves.

Step-by-step guide to moving trees and shrubs

1 If the soil around the plant to be moved is dry, give it a good soaking the day before lifting. This will make your job a lot easier.

2 Dig out a new hole for the plant you are moving. It should be about twice the estimated width of the rootball and the same depth. Heap the soil to one side on a plastic sheet. If a stake is required, position this now.

3 Using a spade, make a slit around the estimated width of the rootball and use this as a guide to dig out a trench around the rootball. Cut off any horizontal roots you come across, using secateurs or a saw if your spade won’t go through them easily.

4 If the plant you are moving is a small shrub, it should be possible just to push the spade under its rootball at an angle of 45° all the way round, then tunnel underneath.

5 Get the spade right under the roots and slide a piece of heavy-duty polythene or sacking underneath.

6 Use a plank to slide the plant out of its old hole, pulling by the plastic or sacking. If the rootball is too heavy to get into a wheelbarrow, either drag it to the new site or tie two stout poles to a strong rope, passed diagonally both ways under the rootball. The plant can then be carried in a stretcher-like fashion by two people.

7 Replant at exactly the same depth as the plant was in its previous position. Planting too deep can kill trees and shrubs.

8 Fill in the hole, firming with your foot as you go. Make sure all spaces between the roots are filled. Attach to the stake if one is being used.

9 Water in the plant, and keep it well watered for the first two seasons while it settles in