Don’t prune plums in winter as this increases the risk of silver leaf infection. For a free-standing plum tree, you will be aiming at creating a bush or pyramid shape. Cordon or espalier plums require different treatment. It is also possible to remove the central leader and grow the tree in an open bowl shape.
Pruning plum trees after planting
- You will have planted in winter when the tree is dormant.
- In early spring (April), before bud break, prune the central leader down to about 60 cm/2 feet above the ground, ensuring that there are at least 3 buds below. These will form the main lateral branches.
Pruning plum trees, second year
- In early spring (April), before bud break, prune the central leader down to a height of about 18 inches, 45 cm, cutting above a bud.
- There should be at least 3 lateral branches. Ensure that they are growing outwards by at least 45° from the vertical, so that the final tree will have a vase shape. Tie down if necessary.
- Prune the laterals back to a length of about 10 inches/25cm.
Pruning established plum trees
- Prune every year in early spring (April), before bud break.
- Remove any suckers growing from the rootstock.
- Rub out any buds growing on the lower trunk.
- Cut out any dead, damaged or diseased wood, and dispose of it as appropriate, removing it from the garden.
- Cut back the central leader down to above a metre above the top lateral branch.
- Remove any weak, crossing or vertical branches.
- Prune branches that did not produce fruit the previous year.
- Trim one-year-old shoots back to six leaves length to stimulate the production of fruit bud for next year.
Pruning a neglected bush plum tree
The objective is to open the centre of the canopy to enable the light to penetrate.
- Try to plan the cuts so that you remove a few complete branches. It is better to remove just 4 or 5 large branches, rather than lots of little snips here and there.
- This pruning should be done in April, but the operation should be performed over several years – on no account try to remodel the tree all in one year.
- Always seal large wounds with heal and seal.
- The tree will react to branch removal by producing lots of new shoots. These can be reduced in July by completely cutting out some of these shoots.
Pruning a poorly-cropping plum tree
It may sound drastic, but poorly-cropping plum trees often react very favourably to a treatment as set out below. This method must be seen as a last resort. Obviously improving microclimate and pollination are absolutely essential as methods to be tried first.
- In the first week of June, remove growth points of strongly growing new shoots.
- In the first week of July: cut back to five-leaf stage and remove growth points.
- In the first week of August: cut out small surplus branches.
- In the first week of September: cut the tree back – shorten the leader and all branches so that the entire tree can be handled easily – ready for lifting. Seal wounds.
- When leaf fall is complete: lift the tree. Dig it out by cutting vertically with your spade about 1 foot/30 cm from the trunk. Cut all the roots back to this length.
- Then plant the tree back in the same hole. Stake and tie the tree to stop rocking movements while roots regrow.
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