In this article, we look at the role pruning plays in maintaining the health and growth of our plants as well as some basic principles so that you can approach the task with confidence.
Pruning is carried out for a number of reasons: to help shape recently planted trees and shrubs (formative pruning); to maintain their current shape; or to reduce plants that have been left to grow wild (restorative pruning). Generally, we want to encourage health and vigour in our plants and pruning can help achieve this. For example, fruit trees and shrubs can be pruned to encourage fruiting.
The basic principles of pruning involve removing dead, dying and diseased growth as well as branches which are crossing or rubbing. Clear space in the centre of the plant if it is overcrowded and use sharp and clean tools to make cuts so that the risk of spreading disease from one plant to another is reduced.
Sharper tools are less likely to crush plant material as they cut and take less effort to use. Everyone has their own preference for pruning tools. Secateurs and loppers can have bypass or anvil type blades. There are a huge variety available and it’s worth trying some out at a garden centre if you don’t already own a pair to see what suits you. See the ‘Equipment to use’ section below for further advice.
When pruning, always cut above a ‘node’ (growth point where buds and leaves originate). This is done as the stem above the growth point will die back to the node and that dead material will be broken down by fungi and bacteria which could transfer to the plant. Ideally, choose an outward facing bud and the cut should slope backwards away from the node, but this is not essential, especially on smaller stems.
With woody plants, branches or side stems should be cut with care so the cut does not affect the main stem or trunk, but not too much should be left as a possible source of infection. By using a knife to reveal the cambium layer, callousing is encouraged. Current best practice discourages the use of wound paints as these are as likely to seal in disease as prevent it from entering.
When reducing the size of established woody plants, it is generally recommended to remove no more than a third of the plant at a time. This prevents the plant from going into ‘shock’ and producing lots of new growth to replace what is lost. Plants that are shocked are likely to produce lots of whippy growth and are prone to suckering from lower down on the plant.
Some plants can withstand and even flourish from more severe pruning regimes. Think of willow and other trees like hazel that are coppiced being cut right down to a low stool. It is always worth doing some research and looking up details for your particular plant down to variety and cultivar.
The best time to prune your trees and shrubs depends on a number of factors but we can make some generalisations that can help us to understand a plant’s needs. In general, deciduous trees and shrubs can be safely cut in the wintertime when dormant, but outside of this period may still be appropriate depending upon the flowering period.
For plants that flower November to June e.g., kerria, ribes, these are best pruned after flowering. If you prune before this, the new growth will not have time to form buds for flowers. For later flowering plants (July to October), they can be pruned in spring down to two or three buds of last year’s growth and they will then have time to send out new shoots and form buds in time for flowering. Evergreen shrubs are also best pruned after flowering.
Using secateurs for a period of time can be hard work on the hands. If you have any weakness in your hands, there are alternatives available that can help. Listed below are some examples:
For more details about cutting techniques and tools if you have a disability, please visit our Carry On Gardening: Pruning.