A good start in life
Trees should generally be planted whilst they are dormant - that is during the winter. With bare root and root balled trees this essential. With container grown trees you may be able to get away with planting at a different time of year, but it is best not to try if you don't have to.
Digging the hole
Before you start to dig, make sure you have checked that there are no underground utilities (eg electricity, gas etc) where you plan to plant your tree.
It's important to get the hole the right size. It should not be too deep - trees should always be planted with the soil at the same level as it was in the nursery. Dig the hole a little deeper and then fill it back slightly to get the tree to the right level.
Your hole should be wide. Around 3 times the diameter of the tree's root ball. On heavy soils be sure to use a fork or the edge of a spade to break up the edges of the hole.
Newly planted trees need watering a lot. It's a good idea to include some sort of irrigation pipe in your planting scheme to ensure that all the water you put on the tree actually gets to the roots. Commercial products are available such as the “root rain”, or you can use a 3m length of perforated land drain pipe. Wrap it around the root ball and leave one end above ground.
A common misconception is that the stakes attached to newly planted trees are there to support the stem. In fact stakes should not support the stem at all.
Stakes should be used to hold the root ball steady and allow the new root system to develop. If you stake a tree use a very low stake and attach the tree to the stake as close to the ground as possible. If you prevent the stem from swaying it will not put on girth as fast and the result will be a weak stem.
Do not hammer a stake in through the root ball of your new tree. Put the stakes to one side to avoid any damage to the roots. You can use a proprietary tree tie to attach the tree to the stake, or a pair of old tights in a “figure of eight” arrangement.
If you are planting a container grown tree remove the tree from the container. If it is a wrapped root ball, carefully remove the wrapping from the upper part of the root ball.
Make sure your tree is straight and start to fill the hole back up. Some people advocate inverting the soil as you do this, so that the top soil goes back in first and subsoil on top. Gently firm down the soil with your heal as you go and take care not to change the levels around the base of the tree. Remember, the tree should be planted at the same level that it was at in the nursery.
One of the biggest threats to newly planted trees is competition from weeds. Clear an area around your new tree of any other vegetation - including grass. This should have a radius of at least 1m. You can use a layer of bark mulch or a mulch mat to help prevent weeds from growing in this area. This has the added advantage of slowing the rate of moisture loss from the soil. If you use bark or chippings, take care not to heap them up around the base of the tree.