Tips for Pruning Formal, Summer Hedges

Formal hedges and topiary need to be trimmed fairly regularly during the growing season (May-September) to keep in shape. A final prune in late summer is recommended for many reasons, one being that any nesting birds are likely to have left by this point rather than earlier in the year. Doing a final cut in August, when summer growth has come to a stop, also helps maintain the shape of hedging through the winter. Completing this task by early autumn also gives cut branches and stems a chance to recover before the weather starts to turn. Here are a few tips to make sure your maintenance pruning a bit easier.

1. Use clean, sharp tools

Cleaning and protecting purners and shears with oil before storing away for winter - © GAP Photos/Friedrich Strauss

Cleaning and protecting purners and shears with oil before storing away for winter – © GAP Photos/Friedrich Strauss

Make sure all cutting equipment is sharp and sterilised before use. Sharp tools make cleaner cuts to branches and stems, decreasing the chance of long-term damage to the structure of the plants. Using un-sterilised equipment also increases chances of passing diseases from one plant to the other, so giving your tools a thorough clean before use is always worth the effort.

2. Use canes as guides

Hedge trimming. If you find it hard to cut hedges, put up two canes to the desired shape. Attach two lines between them to act as guidelines - © GAP Photos/Mark Winwood

Hedge trimming. If you find it hard to cut hedges, put up two canes to the desired shape. Attach two lines between them to act as guidelines – © GAP Photos/Mark Winwood

It can be hard to cut hedges to the exact specifications just by eye alone. To make it easier, create a guide with bamboo canes and string as a frame. This should prevent you from cutting too much back.

3. Keep sheers flat and parallel to the hedge when cutting the top

Pruning Buxus hedge - © GAP Photos/Visions

Pruning Buxus hedge – © GAP Photos/Visions

Adopting this technique when cutting across the top will guide you, and hopefully prevent you from chopping too much off the top or creating an uneven surface.

4. Keep the bottom ever so slightly wider than the top

Knot garden with patterned Buxus hedges. White garden - © GAP Photos/Robert Mabic

Knot garden with patterned Buxus hedges. White garden – © GAP Photos/Robert Mabic

Many formal hedges are cut slightly wider at the bottom than they are at the top, known as a ‘batter’. This slightly sloping curve to the hedge encourages more even distribution of light to the whole hedge, rather than risking dieback and unsightly, bare branches towards the bottom when the bushy top shoots shade out growth below.

5. Cut from bottom to top in sweeping movements when using electric or petrol-fuelled trimmers.

Step by Step - Maintaining a Privet hedge - © GAP Photos

Step by Step – Maintaining a Privet hedge – © GAP Photos

If you have a small hedge, then using manual tools is probably more than adequate. For larger hedges, you may want a bit of extra help from an electric or petrol-fuelled trimmer or chainsaw to save some time. Always follow the safety precautions that come with the tool, and cut a bit at a time, with regular breaks to ensure you are following the correct line. Using a smooth, sweeping action, bring the trimmer from the bottom to the top, allowing the cut foliage to fall away as you do so.