Proper Pruning for Leylandii Trees & Hedges

Leylandii trees (Leyland Cypress) are a very popular choice for hedging, probably because they are relatively cheap, bushy, fast growing, dense and evergreen, making for excellent windbreak and privacy screening all year round.

These are all great attributes and you won’t find a more efficient hedging plant – but woe betide what might happen if you leave your Leylandii hedge unpruned and let it get out of hand!

Leylandii can grow up to three feet a year, so if you don’t keep it in check it will end up being too tall to maintain without a great deal of difficulty, and could end up causing trouble with the neighbours. These conifers are known for causing a number of hot disputes between neighbours, to the point that it would be worth acquainting yourself with the law pertaining to high hedges if you have Leylandii trees on your property.

The Law & Leylandii

Legally Leylandii trees shouldn’t be allowed to grow to taller than two metres – but neighbours can still complain to the local Council if they are shorter than this but still being deemed a nuisance, like blocking out sunlight or a view.

The best way to keep the peace, and enjoy your Leylandii hedge, is to keep it in trim, neat and tidy and pruned to the legal height or below. Be considerate of your neighbours, and if they ask you to trim down your hedge for a good reason comply with good grace.

The Royal Horticultural Society (RHS) has a simple but full explanation of all aspects of the “high hedges” law on their website.

It is obvious, then, that if you are going to grow a Leylandii hedge you’ll need to keep it regularly pruned, and if you have an existing over-grown hedge it will need expertly cutting back and kept in check in future.

When should Leylandii be pruned?

A Leyland cypress (Leylandii) hedge can be pruned during the growing season, between April and the end of August. On an established hedge the top and sides should be trimmed three times during the warm months. A young hedge that is still being formed should be trimmed back at the sides during the first few years, leaving the top shoots until it reaches the desired height, after which the top shoots can be cut during the following spring. It’s best not to trim your Leylandii hedge during very hot or very dry weather.

Can I prune Leylandii in winter?

The final Leylandii trim is best done in early autumn when the trees still have a chance to recover before the onset of winter. Cutting back a conifer in winter will probably result in die back and you’ll end up with a rather unattractive patchy brown hedge, or if it’s a very hard, frosty winter, a dead hedge. Leylandii hedges do not regreen from bare branches.

How do you cut back an overgrown Leylandii?

If you haven’t trimmed your Leylandii hedge for a few years it will have grown too tall to cut back safely, and you’ll need to call a professional tree surgeon. You can cut off the top of a Leylandii trunk to the height you want it to be, but there’s not much you can do about the width. This is because if you cut the mature Leylandii branches back beyond the green growth they will not regrow, and the cut area will stay brown and unsightly.

What is the best shape for a Leylandii hedge?

The ideal for a Leylandii hedge is to trim it (regularly) to establish a A-shape, with sloping sides widening out towards the bottom, so that the sun can penetrate the plant. This shape has to be encouraged gradually from when the hedge is first planted, however. You can’t radically chop an established Leylandii into a particular shape or you will risk creating bare or brown patches where the mature wood will not re-shoot with greenery.

For help with planting, pruning or removing Leylandii trees and hedges across South West England get in touch with Dan Potter and his team of experts at West Country Tree Services.