Renovation/hard pruning

Renovation pruning, which can be considered to be hard pruning for the purpose of renewing a plant, is carried out on woody plants which have become neglected or overgrown. It generally involves the gradual reduction of old growth, so that the plant is less cluttered and encouraged to put on new growth. You should check that the plant will tolerate hard pruning before carrying out these operations.

Plants which grow beyond their required size (particularly shrubs) are often hard pruned to keep them within their boundaries. However, it should be kept in mind that hard pruning encourages young, vigorous growth, so it may be counterproductive in reducing the size of a plant. Hard pruning is also used to even out lopsided growth. Coppicing and pollarding are examples of hard pruning techniques which are often used to rejuvenate trees and shrubs where they respond well to this type of treatment.

Where a plant is diseased you should deal with this before carrying out any renovation or hard pruning. If the plant cannot be cured then it should be replaced rather than renovated. Very old plants may also be unable to survive the process of renovation and new plants should be bought instead.

Renovation or hard pruning should be carried out in autumn/winter for deciduous plants (when they are dormant) and spring for evergreen plants (when they are just starting to grow again), or at the appropriate time for the plant in question if it’s pruned in a different season to the ‘norm’.

Shrubs and climbers

The renovation of shrubs and climbers can be carried out in stages or, if you are certain that the plant will recover, in one go.

Steps for renovation in stages

Year 1 – Remove up to half of the stems at ground level (leave 5-10cm of stem above ground level) or back to the main branches/stems. When doing this you should prioritise removing any dead, diseased, damaged, crossing, congested or weak stems. The next priority is to remove very old stems. If you are dealing with a climber you should remove it from its support first, lay it on the ground to sort out the different stems, then prune it.
Year 2 – Thin out the vigorous growth originating from last year’s pruned areas. Cut back half the remaining, old stems to ground level or back to the main branches/stems. The remaining older stems can be shortened if required to even out the look of the plant.
Year 3 – Remove the remaining old stems (which may have been shortened last year) and continue to thin out the new, vigorous growth.
Year 4 onwards – Prune as normal.

Steps for renovation in one go

Year 1 – Cut all the main branches/stems back to 30-60cm above ground level, with a horizontal cut for shrubs and an angled cut for climbers. You may find it easier to remove the side stems first so you can get at the main stems. Mulch and feed the plant well to encourage new growth.
Year 2 – Thin the new growth to two or three strong stems which will form the main framework for the plant. Remove any suckers growing from the rootstock of grafted plants.
Year 3 – Prune as normal.

Where you are pruning a grafted plant you should ensure that you never cut it to below the graft union (which is usually up to 15cm above ground level, unless it is a top-worked standard).

Trees

Where the tree you are dealing with is large or requires major renovation, you should always call in a professional tree surgeon. Not only will they be able to carry out the work safely, they will also be able to ensure that you achieve the required effect.

Before carrying out any hard pruning on trees you also need to consider any legal or neighbourhood implications, such as if the tree is growing on someone else’s land, if the tree is protected or if pruning the tree will open up a view into a neighbouring garden.

If you are dealing with a small or young tree then you can carry out the work yourself, just ensure that you use the correct equipment and take all approrpriate measures to reduce the risk to your health and safety. You should also consider how you make the cuts to ensure you do not damage the tree and that any heavy branches are removed safely.

Steps to correct lopsided growth

Year 1 – Prune the tips off branch leaders on the stronger side of the tree. Hard prune the growth on the weaker side, prioritising any dead, diseased or damaged stems, so that the growth from all the shorter branches is reduced in length by about a half. This should encourage more vigorous growth on the weaker side.
Year 2 onwards – Remove any stems from the weaker side which are crossing other stems (to prevent them rubbing) and any which are growing in such a way that they will make the crown look unbalanced. Once the sides have evened up (this may take quite a few years) then you can go back to pruning as normal.

Steps to renovate a neglected tree

When carrying out renovation of a tree, only one or two main branches should be removed each year.
Year 1 – Remove all dead, diseased and damaged growth, any crossing branches and any suckers from the base of the tree.
Year 2 – Remove any congested growth (some of which will have grown up following last year’s pruning) and remove/shorten branches to enhance the shape of the tree.
Year 3 – Repeat the year 2 pruning, if required, to further reduce congestion and improve the shape of the tree.

Remember that most conifers do not respond to hard pruning as they cannot re-grow from old wood.

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