There is so much more to pruning than simply just chopping plants back and how to prune plants is probably one of the most common questions I am asked. And so many gardeners have questions about pruning: How far do I need to cut? When is the best time to prune? My shrubs are a tangled mess… Can you help?
And yet there has been so much written over the years about pruning. So why is it so difficult? One of the reasons has got to be that many gardeners tend to cut things back only when they have outgrown their allotted space – and that is often in the growing season when the ‘problem’ occurs. I refer to this as being a ‘reactive’ pruner – somebody who reacts to the growth made by plants.
Cutting back plants when they are in full growth, often in summer, can result in the removal of many or all of the flower buds and creating what I affectionate refer to as ‘dollop-ised’ bushes. They are all round and dollop like – a bit like Tellytubbyland.
What I would like us all to be is ‘pro-active’ pruners. By this I mean that if we understand just a little about how plants grow (in particular woody plants such as shrubs, fruit bushes and trees) then we can cut them back well before they outgrow their welcome and, in most cases, train them to fit the space we want. And the growth cycle of plants is not difficult to understand.
It starts in spring and continues to through to autumn, and cutting back before growth starts will channel all the plant’s energies into relatively fewer buds, lower down on the plant. For plants which bloom in the summer, at the tips of the current season’s growth – like the butterfly bush, Buddleia davidii – then cutting hard back, almost to ground level is ideal. This way ALL the growth will come from the base and the new shoots will be topped with flowers in the summer. It really is that simple and the time to do this is usually late-February to mid-March in the southern and western parts of the UK and late March to mid-April in the north of England and Scotland.
Cutting back the roses
It’s also crucial to prune your bush, shrub and climbing roses at this time of year. And with bush roses – those that are described on the label as ‘floribunda’ or ‘hybrid tea’ – you can be really brutal. Cut these down to a maximum of 5 buds above the base of the plant and you’ll encourage really strong stems that will carry flowers this year. Even if you can’t see buds on the older stems, look carefully for marks and slight bulges which indicate where the ‘nodes’ are (the points where the buds were) and cut back to just above this point.
For climbing roses – which are very vigorous forms of shrub roses – simply prune back all the side shoots and stems to a couple of buds (or nodes) above the point where they come off the main framework of branches which is trained over the wall, fence or arch. Leave rambling roses alone in the dormant season, pruning instead in the summer, after flowering.
Meantime, with shrubs and modern roses (David Austin and Peter Beales roses), it’s best to cut out a few of the oldest, thickest stems right down to the base to encourage new grow from low down. The rest of the strongest stems can then be cut back by a third and any thin (less than pencil thickness), weedy stems pruned out altogether.
How to prune spring-flowering shrubs
For shrubs that bloom on side shoots made in previous growing seasons, it is a little more complicated. These are usually woody plants that flower in the winter or spring months. In essence it is best to wait until the plant has just finished flowering, and then prune out the thickest, oldest, flowered stems right down to the base – as low as you can on the plant. This will ensure that new shoots are produced from the base to create a cycle of regrowth which will stop the plants becoming overgrown.
When it comes to tools, use a pruning saw for branches and stems thicker than 2cm (¾in.). Loppers are ideal for thicknesses of 1-2cm (½-¾in.) and secateurs for the thinner stuff.
Learn how to prune
All this might still sound a but daunting – and I have to admit that it is difficult to sum up the whole of pruning in a single post like this.
So, after more than 30 years as a trained gardener, horticultural lecturer, magazine editor and garden writer, I’m heading up pruning classes that will arm you with all you need to make the right cuts every time. And over the coming season it’s not just pruning that you can learn about – I run both beginner and advanced classes on a wide range of topics that will help you to become a better gardener. These talk the form of private talks and demonstrations which I can offer to individuals or gardening groups, as well as those which I provide for readers of BBC Gardeners’ World Magazine.
Find out about my next pruning Masterclass, or any other gardening courses on offer by going to my Events and Tours page, and selecting the Gardening courses option.