We planted a row of 7 beech hedges, 7 years ago. They seem to be doing well, however are reaching for sunlight because they are partially overshadowed by a larger maple. Of course we would like them to grow together more like a privacy screen. They are currently about 7-8 feet tall, which is a little taller than we would like. In our GTA climate, when is the best time of year to prune, and how much should we take off at one time? I think 6.5 – 7.0 feet would be our ideal.
Thank you for contacting the Toronto Master Gardeners.
Beech (Fagus sylvatica) is one of the most popular plants for hedging due to its beautiful leaves and their ability to hang onto the leaves right through winter.
This tree tolerates a wide range of soil conditions and prefers to be positioned in full sun or partial shade. Beech trees usually put on two flushes of growth per year; the first flush in the spring and a second smaller flush in late summer. Ideally, the hedge should be cut back after each flush.
Pruning your hedge in early June once the first flush of leaves has expanded will keep your hedge healthy and will allow lateral buds to grow out causing your hedge to fill in and become bushy.
If you wish, you can prune your hedge in early August. This allows the hedge to produce a second smaller flush of leaves. These are the leaves that will stay on the branches through out the winter providing year-round screening. If you are unable to prune in August, then wait until early June.
Regardless of the time of year, any dead, diseased or damaged branches should be pruned out. The general rule of pruning is that no more than 1/3 of the plant should be removed at any one time.
This website provides step by step instructions along with illustrations on how to prune a beech hedge:
You might also which to thin out your maple tree to allow more light to filter through to the beech hedge. To find a certified professional arborist visit the Ontario branch of the International Society of Arboriculture here.