When you prune shrubs at the right time, they grow properly, flower abundantly and look good. When you prone them at the wrong time, the opposite happens. Those shrubs could even become vulnerable to cold weather, pests and diseases. Therefore, timing is crucial to the pruning of shrubs.
So, what time of the year should you prune shrubs (UK)? It depends on the type and flowering time of the shrub. More specifically, it depends on whether the shrub is deciduous or evergreen and whether it is summer-flowering, spring-flowering or non-flowering.
This article will look at when to prune shrubs in these five categories. Then, we’ll cover some of the basics of shrub pruning, including tools, techniques and common mistakes.
The Best Time to Prune Shrubs in the UK
Here is when to prune deciduous and evergreen shrubs, including non-flowering, spring-flowering and summer-flowering ones.
Winter is the best time to prune deciduous shrubs. The shrub will be dormant during this period. So you won’t have to manoeuvre around foliage or disrupt growth. Recovery will also be faster because of all the food accumulated in the shrub’s roots and trunk.
You can prune deciduous shrubs during the growing season, too. This gives the new growths more time to mature before the next growing season. However, when using this method, allow the shrub to bloom before pruning it.
This way, you won’t disrupt its flowering for that year. Flowers contribute a lot to the aesthetic appeal of deciduous shrubs. So, let the shrub bloom before pruning it.
Waiting also allows the shrub to focus on one thing at a time. It won’t have to split its energy between flowering and sprouting new growth. It can do one, then the other. Finally, waiting allows you to identify productive and unproductive branches. Now, you know what to remove and not remove.
Therefore, aside from winter, you can also prune deciduous shrubs after they finish flowering. This means you can prune spring-flowering deciduous shrubs in spring and summer-flowering ones in summer. Spring-flowering deciduous shrubs include fuchsia, hydrangea, hibiscus and forsythia. Summer-flowering deciduous shrubs include Weigela, buddleia, kerria and Philadelphus.
The only exceptions are non-flowering shrubs. You can prune them any time of the year. However, there are barely any deciduous shrubs of this kind. The only options are those with inconspicuous flowers, such as burning bush, northern bayberry and common winterberry.
Evergreen shrubs don’t go dormant in winter. So, you can’t use the “wait until winter” approach. If you prune evergreen shrubs in winter, you will cut limbs that still contain food and expose the rest of the shrub to winter damage. Therefore, you shouldn’t prune evergreen shrubs in winter or even autumn.
Prune them during the growing season instead, after their yearly bloom. This means you should prune spring-flowering evergreen shrubs in spring, summer-flowering ones in summer, and non-flowering shrubs between spring and summer.
Spring-flowering evergreen shrubs included winter heath, Japanese rose, Andromeda and rhododendron. Summer-flowering evergreen shrubs include cinquefoil, shrub rose, spirea and potentilla. Finally, non-flowering evergreen shrubs included inkberry holly, spruce, boxwood, mirror bush and arborvitae.
Key Considerations for Pruning Shrubs
Now that you know when to prune shrubs in the UK, let’s discuss some tips for actually executing the job.
Assess the Shrub Type and Health
Shrub type determines timing, while health determines scale. For example, you can prune a deciduous shrub in winter but not an evergreen one. Also, you can’t prune a healthy shrub as you would an out-of-shape one.
Choose and Prepare your Pruning Tools Properly
You need a range of pruning tools. Secateurs are perfect for pruning small shoots but they can’t handle thick branches. For that, you need pruning saws. You should also get lopping shears for high and hard-to-reach branches.
Finally, your pruning tools must be sterile and sharp. You can use a bleach solution or rubbing alcohol to sterilise them.
Be careful when using heavy machinery or working at height. You should also get protective clothing and climbing or telescopic tools.
Step-by-Step Guide to Pruning Different Types of Shrubs
Pruning is simple once you understand the basics. There are two primary goals. The first goal is to reduce the shrub by 30%, focusing on removing undesirable limbs. Those undesirables included limbs that are dead, damaged, diseased, poorly positioned, crossing other branches and pointing in the wrong direction. After removing those, cut back the desirables (aka healthy, productive branches) by 20%.
The second goal is to ensure pruning doesn’t make the shrub vulnerable to cold, pests and diseases. That’s why you must prune at the right time and use sterile sharp tools. 45-degree cuts, sloping downwards, will allow the wounds to heal faster. You can also treat the cuts with tree sealant. Finally, don’t forget to water and feed the shrubs after pruning.
Pruning Healthy Shrubs
Healthy plants only need light pruning. So, don’t remove more than 30% at once, even if that means you must prune more than once yearly. This is the case for formal hedges. You have to prune them twice a year to maintain their shape. Do this in spring and summer.
One of those pruning sessions will have to happen before the flowering period but there is no alternative. That’s why you must prune lightly in this situation. It will reduce the negative impact on flowering. Above all, no matter when or why you prune, always leave the top of the shrub wider than its base.
Pruning Out-of-shape and Ill-maintained Shrubs
An out-of-shape shrub needs hard pruning. That’s the only way to rejuvenate it by triggering new growth and controlling its shape. However, you’ll probably have to do it over a couple of years. It’s not every shrub that can take extensive pruning in one go. Many deciduous shrubs can, but most evergreens can’t. So, to renovate an evergreen shrub, you have to stagger the process over three years.
Common Pruning Mistakes and How to Avoid Them
Here are three mistakes people make when pruning shrubs.
Over-pruning makes recovery difficult. It depletes the shrub’s food reserve and protection. As a result, the shrub may never fully recover, leading to permanent damage. So, avoid this by never removing more than 30% of a shrub in each session. You should ensure the shrub has enough one- and two-year-old branches. They are the flowering branches.
Incorrect timing impairs growth and makes the shrub vulnerable. So, never prune evergreens in winter. Prune them in spring or summer. Deciduous shrubs are the only ones you should prune in winter. Above all, ensure the shrub has enough time to recover before the cold and flowering seasons start.
Neglecting Tool Maintenance
Single clean cuts are crucial to the pruning process. You can’t make those with dull pruning tools. However, sharpness is not the only attribute that matters. Sterility also does those. Dirty and non-sterile tools can spread infections.
There you have it. The answer to your query depends on the type and flowering habit of the shrub. So, figure out if your shrub is deciduous or evergreen. Find out if it is spring-flowering, summer-flowering or non-flowering. Then, use the information in this article to determine the best pruning time.