How we test hedge trimmers

We've tested a wide range of hedge trimmers over the years, covering big-name brands including Black & Decker, Bosch and Stihl. 

Our expert testing guide explains what we look for in a hedge trimmer and what makes a Best Buy.

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Video: how we test hedge trimmers

Why our hedge trimmer tests are different

Hedge trimmers take the hard work out of keeping your hedges looking neat, and a well-cut hedge will make the whole garden look better. We carry out independent, scientific tests designed to discover how well hedge trimmers cope with challenging hedges and whether they leave them looking crisp and neat or chewed and ragged. 

Our reviews show whether or not a hedge trimmer can cut a variety of hedge types. We also pay attention to the speed of a hedge trimmer, ease of use and safety features.

What are Which? Best Buys and Don't Buys?

Best Buys are given to hedge trimmers that impress the most in our rigorous tests. A model has to achieve 81% or more to be a Best Buy and anything scoring below 45% is highlighted as a Don't Buy that we think you should avoid. 

• Best Buy hedge trimmers are robust, versatile, efficient and easy to use. They leave a flawless finish, cutting twigs cleanly and proving easy to use.
• Don't Buy hedge trimmers are a pain to use. They don't have the power to cut through branches, resulting in a messy hedge.

How is the Which? score calculated?

Each of our hedge trimmer assessments make up part of the overall test score, which is a percentage figure we award to each model. Some assessments are more important than others and so carry different weights.

As electric, cordless and petrol hedge trimmers have different strengths and weaknesses, we adjust our test weightings accordingly.

Electric and petrol hedge trimmers

• Cutting tests 50%
• Ease of use 50%

Cordless hedge trimmers

• Cutting tests 40%
• Ease of use 40%
• Battery life 20%  

Hedge trimmer cutting quality

Key question: how well does the hedge trimmer cut a variety of hedge types? 

There are many shrubs that can be cut to form a hedge. Some, such as cherry laurel, have tough stems and leathery leaves. Others, such as privet, have thin, whippy stems and soft leaves. A good hedge trimmer should be able to cut through all types of growth, and we've developed our tests so that we now cut the most common types of hedge. 

We cut the following hedges: 

• Conifer hedges
• Deciduous hedges
• Laurel hedges
• Privet hedges. 

Our three testers each cut at least 10m² of each hedge type with each hedge trimmer to see how well they cut, how quickly they cut and how easy they are to use.

Not all hedge trimmers leave a neat finish. Some don't make a clean cut but rip through stems, leaving long 'tails' that make the whole hedge look untidy. Some don't cut neatly through leaves, but chew them up, again leading to messy-looking hedges.

Pick the right hedge trimmer for the size of your garden. We round-up the best hedge trimmers for small and large hedges. 

Hedge trimmer speed

Key question: how quickly will the hedge trimmer cut?

Our testers cut at least 20m² of conifer, deciduous and evergreen hedges and time how long it takes to cut this amount of hedge.

The times are then averaged to make sure the time taken is representative of each hedge trimmer's performance and isn't affected by the user cutting through a particularly tough or gappy section of hedge.

Hedge trimmer ease of use

Key question: is the hedge trimmer easy to set up and use for the first time?

Three testers assess each hedge trimmer for ease of use, taking into account how easy they would be for an older or less able gardener to operate. 

We rate the machines on 18 criteria, including how easy they are to carry around, how comfortable the handles and switches are, how simple they are to use for vertical or horizontal cutting and whether noise, vibration, weight or balance are a problem.

Read our advice on how to cut a hedge. 

Hedge trimmer battery life

Key question: how much hedge can I cut with a cordless hedge trimmer? 

Battery technology is improving rapidly and cordless hedge trimmers save the hassle of trailing leads on electric models and the weight and noise of a petrol hedge trimmer. 

We cut the same three hedge types as with electric and petrol models, but rather than stopping after 10m², we carry on until the battery has been exhausted. We note how many minutes this is and calculate how many metres of hedge we've cut in this time, and how well the trimmers have cut. 

We rate how easy the battery is to remove and refit, and time how long it takes for the battery to recharge.

New to hedge trimming? Find out the right time to cut your hedge?

Hedge trimmer safety

Key question: is the hedge trimmer designed in such a way that it's impossible to injure yourself in normal use?

We check hedge trimmers for electrical and mechanical safety. Features we look for include:

• Two separate switches so you have to keep both hands on the machine.
• Blades that stop the instant you release one of the switches, so touching a still-moving blade is impossible. 
• Blade extensions – fixed teeth that extend well beyond the cutting teeth, so you can’t do serious damage if you accidentally brush the trimmer against your leg.

Over the 30 years we’ve been testing hedge trimmers, safety features have improved considerably. In the early days we campaigned to improve safety features and these have now been incorporated into international standards and adopted by all manufacturers.

Do I need a long-reach hedge trimmer? Find out if they are the right option for you. 

Is the battery replaceable?

Lithium-ion batteries always deplete and eventually die over time, and at Which?, we believe that cordless products should last longer than the batteries they come with. That's why we no longer give cordless hedge trimmers Best Buys if spare batteries cannot be bought from the manufacturer – no matter how good the hedge trimmer might be.

What is the future for petrol-powered hedge trimmers?

With sales of new petrol and diesel cars set to be banned by 2030, could petrol gardening tools be next?

By improving the appearance of outside spaces, we may be inadvertently contributing to environmental damage. 

Unlike cars, petrol garden machinery doesn’t have catalytic converters to reduce the amount of pollutants that enter the atmosphere- likely due to the cost of the materials bumping up the retail cost and because the UK regulations are not as strict for garden tools.

Californian Governor Gavin Newsome has signed legislation banning the sale of petrol gardening equipment by 2024. 

We're already seeing less petrol launches from manufacturers, who appear to be focusing their attention on cordless tools.

Cordless tools produce zero emissions and are quieter, offering a better option for the environment and our health.

We’re finding that cordless tools are now rivalling petrol in their power and, in some cases, out-performing, so many consumers have already made the switch.

Browse all our hedge trimmer reviews to find your perfect model.