Few things can match the impact a well-kept hedge has on the aesthetics of a garden. And if you go a step further by trimming that hedge into an interesting shape or adding extra features to create an even more interesting hedgerow, your garden could look and feel like perfection.
On the flip side, even fewer things can match the impact an unkept hedge has on the aesthetics of a garden. Just imagine the unsightly look of overgrown branches and stray shoots, or bare patches and thin foliage. In other words, if your hedge(s) looks unkept and unhealthy, your entire garden does too.
My point is that hedges have a dramatic effect on the looks of a garden and the entire property. Therefore, it is important to prune them properly. This will encourage the dense and healthy foliage you want. It will also allow you to maintain them at the desired size and shape.
But you probably already know that, which is why you are on this page, trying to figure out the best time to trim hedges. Well, the short answer is to prune your hedge(s) once or twice a year, in late spring or summer. This should be more than enough for most hedges.
The long answer is – it depends on the type of the hedge and the pruning. By this, I mean, is it a formal or informal hedge? And are you pruning for formative or maintenance reasons? Your answers to these questions will determine the when, how and frequency of hedge trimming.
So, at the end of the day, it all depends on the needs of the hedge plant. Therefore, before taking you through a pruning calendar for the most popular hedges in the UK, I need to explain the factors that determine when you should trim hedges.
The type of the hedge
This is probably the most important factor that affects every aspect of hedge trimming, including the when, how and frequency. There are two types of hedges based on how you choose to train them.
This type of hedge is closely-clipped and restricted to a desired shape. It is not allowed the liberty to grow into its natural shape. In order to maintain the shape of a formal hedge, you have to prune it at least 2 to 3 times a year.
Most evergreens are trained as formal hedges. Examples include fast-growing conifers like western red cedar, leylandii, yew, Lawson cypress, and taxus, or slow-growing stocky deciduous plants holly, holm oak, spindle, boxwood, beech, hornbeam, privet, and laurel.
Unlike a formal hedge, an informal one is not closely-clipped or restricted to any shape. It is allowed to grow into its natural shape. As a result, you only have to trim it once a year. So, informal hedges are relatively low maintenance.
You can even go a few years before trimming. However, if you intend to try this approach, you should still prune the hedge slightly to keep it neat. Still, informal hedges don’t have to look as neatly clipped as their formally-trained counterparts. That is the point. You want them to get naturally bushy, and bear flowers and fruits in cases of flowering plants.
That is why flowering hedges tend to be the most common type of informal-trained hedges. However, any deciduous plant will do. The most common examples of informal hedges in the UK are blackthorn, dog rose, lilac, butterfly bush and hawthorn.
The type of the hedge pruning
Now it is time to talk about the second major factor that affects the when, how and frequency of hedge trimming. There are two types.
Formative hedge pruning
The purpose of this type of pruning is to train a hedge to grow into a desired shape and direction. It also encourages healthy growth and dense foliage. Formative pruning is usually executed on young/newly-planted hedges in their first two years. For some plants, the third year is also included.
The best time for formative pruning is late winter or early spring in preparation for the growing season. It is important to perform this pruning (early) on new hedges. However, the process will vary depending on the hedge and plant(s) involved.
Maintenance hedge pruning
As the name suggests, the purpose of maintenance pruning is to maintain the shape and looks of a hedge. However, like any other form of hedge cutting, it also stimulates healthy growth and dense foliage.
Maintenance pruning starts after the second or third year of planting. The best time for it is summer. It mostly involves trimming stray shoots and overgrown branches. However, like any other form of hedge cutting, the process will vary depending on the type of hedge and plant(s) involved.
So, when should you trim hedges?
Now that you know the two factors that determine the how, when and frequency of hedge trimming, let’s talk about how they play together.
When should you trim formal hedges?
Remember that the point of formative pruning is to train the hedge and encourage healthy growth. Therefore, it is important to start as early as possible when the hedge is still young and easy to influence. So, prune after planting.
Here is the process, depending on the type of plant involved.
- Slow-growing deciduous shrubs: Trim off 1/3 of the plant after planting. Then in autumn, trim off 1/2 of the new growth. Repeat this in the second year.
- Fast-growing coniferous plants: Trim straying shoots after planting. Leave the leading shoots. Then in summer, trim the side shoots.
Maintenance pruning should start 2 to 3 years after planting. Just cut back the branches to the desired size. Then clip straying shoots until the lines and edges are level, and the desired shape is formed.
When should you trim informal hedges?
Start soon after planting. Trim the top by 1/3. Then come autumn, trim off 1/2 of the new growth. Clip the side shoots too. This will encourage dense foliage.
Prune flowering hedges after the flowering season starts or after the fruiting season ends. By pruning after flowering, you can make an informal hedge look like a formal one. Most people prefer this. However, if your hedge produces nice flowers and berries, it may be worth waiting until the end of the fruiting season.
The maintenance trimming process is the same as earlier. Only on a smaller scale and less frequently. Just cut back the branches to the desired size. Then clip stray shoots until the lines and edges are level and the desired shape is formed.
A hedge-pruning calendar for the most popular hedges in the UK
Here is the hedge-pruning calendar, as promised. Now, all you have to do is check if your hedge is on the list.
- Privet hedge: Prune it 3 times yearly, anytime from May to August. If it overgrows, cut back hard in April.
- Leyland cypress hedge: Prune it 3 times yearly, between April and August.
- Yew hedge: Prune it once yearly, between August and September. If it overgrows, cut back hard in April.
- Beech hedge: Prune it once or twice yearly, between August and mid-winter. If it overgrows, prune hard in mid-winter.
- Hawthorn hedge: Prune once or twice yearly in June and later in autumn. If it overgrows, cut back hard in winter.
- Holly hedge: Prune once a year, in late summer. If it overgrows, prune hard in spring.
- Escallonia hedge: Prune 1 or 2 times yearly, in May and late August. If it overgrows, cut back hard in June.
- Laurel hedge: Prune once yearly, in July or August. If it overgrows, prune hard in spring.
- Berberis hedge: Prune once yearly, after flowering.
When should you avoid pruning hedges in the UK?
If you are in the UK, avoid cutting hedges or trees with nesting birds. If you did, you’d be breaking Section 1 of the Wildlife and Countryside Act 1981.
So, check the hedge properly before you start trimming. If there is a wild bird nesting in it, you will have to wait it out. The nesting season lasts from February to August. If you don’t want to wait, you can try to get a derogation.
What tools do you need to trim hedges?
Here are three main tools you need when pruning hedges.
- Shears: This is the most common tool for pruning. Either long arm or hand shears will do, depending on the situation.
- Secateurs: It is better suited for selective and even trimming. Plus, there is less risk of damaging the leaves.
- Mechanised hedge trimmers: This is usually either an electric or a petrol hedge trimmer. Mechanised trimmers are better suited for bigger jobs.
When trimming tall hedges, you will probably need scaffolding or a tool with an extended hand. Finally, don’t forget safety equipment like sturdy gloves and safety goggles.
13 tips for pruning hedges
Hedge cutting is a time-consuming task. It can also be more complex than you think, especially if the desired shape is complicated. So, if you plan to take on the task yourself, you need all the help you can get.
Here are some tips to make the job easier and more efficient.
- Ensure the pruning tool is sharp: This will make the job easier and faster. It will also reduce the risks of mistakes. Plus, powered tools tend to overheat if their blade is too dull for the job.
- Don’t prune by eye: Use something to guide your eyes. If not, you will have difficulty cutting even lines, not to mention getting the desired shapes right. So, try using strings or frames for guidance.
- Cut the hedge upwards: Start low and gradually work your way upwards.
- Prioritise multiple small trims over a big one: Trim in stages. This will reduce the risk of mistakes like over-pruning.
- Don’t cut through leaves: Cut through shoots instead to avoid unsightly leaf damage. This is why you should use secateurs or loopers for the final trim.
- Never prune dry evergreens: Wet them first.
- Keep your hedge(s) slightly tapered upwards: This means the bottom should be slightly larger than the top. Some people call this “cutting to batter”. It ensures the lower parts get enough sunlight.
- Consider using a cane to support the leading shoots: This is helpful for young coniferous hedges. Just drive the cane into the ground and tie it to the shoot.
- Keep the blade of the pruning tool parallel to the surface of the hedge: This makes it easier to get even trims. So, whatever tool you are using, keep the blade parallel.
- Use mechanised hedge trimmers in wide swinging motions: This also makes it easier to get even cuts.
- Brush off trimmings: They can block sunlight and airflow, thus encouraging dampness. The result is a perfect condition for fungal infestation.
- For ageing and unhealthy hedges, prune hard into old branches: This will stimulate the growth of new shoots. Sometimes, hedges require fertilization. If possible, use organic manure.
- Prune the side shoots if you want to encourage dense foliage: Again, you can use manure as needed.
So there you have it. I hope you have figured out the right time of the year to cut that hedge. From what we have discussed, you can see that it depends on the type of hedge and the plants involved.
So, if your hedgerow has different species of hedges planted within it, you have to consider the needs of each species. Likewise, if your hedgerow has a complex shape, you will need to prune it frequently to maintain that shape.
However, all this information only applies to hedges within your garden. For boundary hedges, it may be better to speak to the other party or your local council before taking action.