How to trim your hedge: timing, technique and tool maintenance

The Right Time to Prune

Majority of hedges only require two trims annually: a thorough trim in late spring after the new growth has emerged, and a more casual tidy-up in late summer to maintain the shape.

In spring, trim off any straggling branches and prune back about two-thirds of the new growth.
The hedge should be fine-tuned in the summer, with uneven growth clipped and branching encouraged. Certain species, such mature thuja, fake cypress, cherry laurel, berberis, and yew, only require an annual pruning.

Whatever the species, pick a dry, slightly overcast day for pruning as bright sunshine can scorch fresh cuts, whilst frost can make them slow to heal and more brittle.

Proper trimming technique matters

Here’s how to get clean, professional-looking results with less effort:

The healthy hedge profile
Always trim the sides first, keeping the base slightly wider than the top. This allows sunlight to reach the lower branches preventing the hedge from thinning out from the bottom up. Working upwards also helps the clippings to fall away, rather than masking what you still need to cut.
Smooth and fluid strokes
Instead of making quick cuts, make long, sweeping motions. Hold the blade at an angle of 10-15° to the surface, if the blade is kept flat the leaves will get polished and if the blade is steep then the leaves will get chewed. To avoid ridges, overlap each pass by a few cm and simply let the blades do the work.
Curves and corners
Trim each face flush first, then make a single, decisive pass to crisp the corner. When handling curves, slightly roll your wrists and move in short arcs, building the curve in overlapping ‘tiles’, rather than one risky sweep.
Young vs. mature hedges
While mature hedges may withstand more forceful trimming, younger plants need to be gently shaped to promote growth. Adapt depth and pressure to the maturity of the plant. A more severe trim can be required if your hedge has become patchy or uneven. Except for yew, most conifers won't resprout from old wood, so proceed with caution.

Remember the Wearable Parts

Maintaining your hedge requires routine pruning, but taking care of your trimmer is just as crucial. Simple practices like wiping down the blades after each use to avoid sticky sap accumulation, lightly oiling the machine to lower friction, and keeping it in a dry, dust-free location to protect it in between jobs can make a big difference. Even while these minor adjustments reduce wear, your trimmer will eventually need to have some parts replaced to guarantee that it cuts safely and cleanly.

Here’s what to watch out for:

Blades: Dull or damaged blades tear rather than slice, resulting in messy cuts that put stress on the plant. If you notice frayed leaves or need to push harder, it’s time to sharpen. After several sharpenings, replace them. A good rule of thumb is to check the blades after every 20 to 30 hours of use.
Blade guard and tip protector: These absorb the impact, so your blades don't. Prior to storage or transportation, replace any that are cracked, bent, or missing before storage or transport.
Air filter (petrol models): If you use your hedge trimmer frequently, check the air filter monthly during the cutting season. If it’s clogged with dust or oily residue, replace it. Restricted airflow reduces engine life.
Spark plug (petrol models): Replace spark plugs once a year, or more frequently if the engine is difficult to start or runs rough.
Fuel filter (petrol models): Replace after approximately 100 hours of use to ensure clean fuel flow.
Battery packs (cordless models): Batteries lose capacity over years, not weeks. If your runtime is noticeably shorter than when new and does not allow you to finish your work in one go, it’s time for a replacement. It is always a good idea to buy a second battery to avoid downtime.

Find the replacement part that suits your model

Finally

Operating a hedge trimmer for pruning is about precision, not speed. Investing a few more minutes to maintain your trimmer and hedges can pay you in the form of healthier plants and a tool that will last for many seasons. Replacing wearable components when they begin to age is an easy and cost-effective solution to keep your hedge trimmer operating like new and prolonging its life.