Hedge trimming or how to trim hedges is an art form that takes years to perfect, and managing your own pristine (or wild) hedge is unique to you.
OK, so your standard garden hedge might be a rectangular box or privet, but I guarantee that yours is narrower, wider, taller, shorter, or more or less ornate than your neighbor’s.
We’ve got no intention of telling you how to prune your garden here, but we’ve got dozens of helpful hints and tips to keep the perfect garden hedge.
Our guide on how to trim hedges has details on everything from when to cut, right back to basics like the best hedge plants for your garden.
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What is a Hedge?
Traditionally, hedges were used as a budget way to divide properties, fields, and agricultural sites. They were less costly than stone walls or kilometers of fencing, and easy to replace if damaged.
Today, hedges are beautiful, ornate boundaries to our gardens, and help to divide areas of our plots into manageable chunks.
Types of Hedges
When you first start thinking about hedging plants, it’s important to think about what you’re trying to achieve. Hedges can be a great way to tidy up an otherwise unruly garden, but they can also be bushy, informal masses of foliage that welcome wildlife into your yard.
Formal Hedges
When most of us think of hedges, it's a formally pruned box or privet that springs to mind; rows of neatly trimmed rectangular hedges that firmly state the beginning to a garden.
You can create formal hedging very quickly, but pruning depends on the type of plant you choose to start with.
Informal Hedges
Informal hedges are more about the display, and floral elegance, with roses, or blousy hydrangea flowers drooping out from neatly trimmed edges.
They can be allowed to grow as tall as you like but need pruning at the right time to guarantee a good display every year.
Native Hedges
Native hedges immediately conjure up images of agricultural landscapes, with beech and maple hedges bordering fields, with ivy strewn through the top growth.
But with recent years leading many gardens to more sustainable ways to manage their gardens, many are turning back to our native plants and shrubs to provide habitats for wildlife.
How to Care for a Hedge
Hedges of all types need a few basic things to help them establish, but with so many hedges to choose from, caring for each type is unique to the species, genus, or specific cultivar.
When you plant any hedge plant though, it’s essential to keep the roots wet for the first few weeks. Water each plant with a full bucket of water once a week, so roots are encouraged to grow downwards, rather than sitting at the surface.
After that, water once a fortnight through their first summer, and leave through winter. Water well when new growth appears in spring, and then leave your hedges to their own devices in their second year.
Some deciduous hedges benefit from a mulch of grass clippings or compost in spring to help feed them, but rarely need any specific feed.
How to Trim Hedges
There are no set rules for trimming hedges, but we’ve got some basic rules on how to trim hedges and keep them looking happy and healthy.
Formal Pruning
Formal hedge pruning involves keeping hedges looking crisp and traditionally neat. It can involve closely clipped curves, or tightly constrained corners, but there is always one thing in common; no fly-away stems, sticking out beyond the main structure of the plant.
Deciding to keep a formal hedge requires the right plant to start with: box, privet, holly, and hawthorn create great formal hedges as they can be kept to the same size for decades.
Thinning
Thinning is essential with formal hedge pruning as you need to keep the center of the plant open and well aerated to prevent fungal problems, and to prevent branches rubbing against one another.
To thin hedges, just trace back the main branches and remove them, aiming to maintain the thick, full appearance on the outside.
Shearing
Shearing regularly is key to keeping formal hedges looking good. In many ways, keeping hedges crisp can hide the sins of the rest of the garden. Even overgrown, weed-filled borders, can look intentional when backed by a tightly clipped formal hedge.
Shearing can be done with shears or electric hedge trimmers. The idea is to cut at least once a month, remove anything growing beyond the main shape, and never cut back into the main shape.
Informal Pruning
Informal hedge pruning is much more akin to pruning shrubs. Essentially, you’re pruning based on the plant’s needs, usually to encourage flowering or fruit.
When flowering, or fruiting, has finished, simply cut back the flowering stem by 5-6 nodes. Cut just above a node (leaf or bud) to promote new growth that will flower or bear fruit the following year.
Pruning this way allows hedges to grow to their natural height and width, and provides an informal border around your entire garden. Choose juniper, quince, lilac, fuchsia, or forsythia for the best informal hedges.
Topiary
It sounds intimidating, but topiary is a gardening art form that is at risk of being forgotten. While we associate it with stuffy gardens, filled with ornate herbivorous sculptures, it can be as simple as hedge balls, dotted around the garden, or arches cut through hedges to create interest.
Achieving good topiary takes patience, but by regularly pruning, and topping hedging plants, then allowing them to fill out a few inches per year you can create sturdy frames to accommodate any shape.
A-Shaped Hedges
Regardless of what type of hedge you’re trying to grow, consider what happens in nature. All shrubs grow with a peak, tapering down to their wider base.
This is so that light can pass over every surface, promoting flowering, and even growth across the entire plant. Avoid pruning perfectly vertical lines in formal hedges or informal hedges.
Taper them slightly to the top to create an A-shaped hedge, with a flattened top. This way, you’ll have healthier hedges that have healthy growth from every angle.
When to Trim a Hedge
Some hedges need trimming almost weekly through late spring, with box and privet being the worst culprits. However, any significant pruning work, particularly for native hedging plants, should be done in late summer or late winter, when there is less chance of disturbing nesting birds and wildlife.
Common Hedge Trimming Mistakes
There are a few really basic mistakes that we can all be guilty of when pruning hedges, but like most plants, they will recover. We’ve put together a list below of the most common hedge trimming mistakes, so hopefully, you can steer clear of them next year:
- Cutting into dead wood on some hedging plants will prevent new growth. Try to cut to new growth, or wood with buds below the cut point to allow for regeneration.
- Pruning before flowering will stop flowering this year altogether. Always aim to trim hedges after flowering, or after fruiting.
- Leaving topiaries to grow to its height too quickly. Topiary takes time, and it’s important to continue pruning rather than allowing everything to grow upward at once. This can cause hollow sections below any shapes you might eventually form.
- Using dirty tools spreads infection. When pruning boxwood in particular, it’s essential to disinfect your shears or pruning tools every few meters to prevent inadvertently spreading disease.
Best Tools for Hedge Trimming
I’ve always liked trimming hedges the old-fashioned way, with a good sharp pair of shears, but there are much faster ways to do it these days, with petrol or battery-operated cordless power tools that make light work of topiary and formal hedging.
But it’s important to keep a good stock of tools too, like powerful secateurs or loppers for thicker branches and thinning, or pruning out dead wood. Check out our review of the best tree pruners for 2022 here.
Equally, one tool that people often forget with hedges is a spade. Most hedges are perennial and will send up young plants from their roots called volunteers.
These should be removed to prevent competition at the roots, but can easily be planted elsewhere in the garden.
How to Clean Hedge Trimming Tools
It’s important to clean hedge trimming tools regularly even while using them as they are in constant contact with fresh foliage, which is very susceptible to fungal infection due to the regular damage to the leaves from trimming.
To clean your tools, keep a bucket of hot water mixed with detergent. Regularly dip your secateurs in the mixture. This helps to clean sap, and make for crisper cuts but also kills bacteria and funguses.
When you’re finished, and before you start, scrub your secateurs with a stiff brush then wipe them dry.
Hedge Trimming Frequently Asked Questions
When should you trim young hedges?
Trimming young hedges is different from trimming established hedges, and is referred to as formative pruning. Formative pruning involves cutting back 1/3 of the new growth in winter or early spring.
This should be done until the hedge reaches your desired height to allow for a strong mesh of growth at every level.
Is it better to prune hedges in winter or spring?
If you are pruning back an overgrown hedge, wait until early spring, when new growth is about to kick into action and you can see buds beginning to form along the branches.
Pruning in winter means creating open wounds that will heal much slower than in spring.
How far can you cut a hedge back in one go?
Depending on the type of hedge, you can either cut right to the ground or just a few inches. If you’re unsure, check along the old stems for signs of buds, or live nodes.
These are where the plant will regenerate. Some coniferous hedges will not regenerate below their current foliage, so should only be pruned lightly.
Who is responsible for cutting a boundary hedge?
Boundary hedges are the shared responsibility of both neighbors. If your hedge is overgrown on their side, it is their job to cut it, if theirs is overgrown on your side, it is your job to cut it.
Personally, I believe it is always worth taking care of your whole hedge yourself, as your neighbor may have different plants than you.
Now You Know How to Trim Hedges and the Best Hedging Plants for Your Garden
Hedges can be anything to anyone, so your hedge can be a perfect reflection of your garden, or it can be a neat, formal boundary that defines its edge. It’s entirely up to you, but it’s essential that you get to know your hedging plants, and what they need before jumping with secateurs.
I hope this guide to how to trim hedges answers all your questions, but if not, check our other articles about hedging plants linked above for more information about how to care for specific types of hedging.