How to prune garden trees for privacy AND light

Posted By: Alexandra Campbell On: January 2nd, 2015 In: Gardening know how

The way you prune garden trees will make a big difference to your garden’s privacy and light.

Trees mask ugly views, and stop neighbours peering in. But they also shade your garden.

When garden renovation expert Posy Gentles told me about a French technique called ‘transparent pruning’, or la taille de transparence, I wanted to know more.

Vasterival gardens transparent pruning

The garden at Vasterival is heavily wooded, but ‘transparent pruning’ ensures that enough light comes through for lawns and mixed flowerbeds.

Trees create privacy

Even the most tree-loving gardeners cut down trees when they move to a new house. The tree, probably planted for a very good reason (sometimes only revealed when it is gone!), has usually got overgrown. Straggly, dense and too big for its boots, let alone your garden, it blocks out light.

When I first lived in South London there were hundreds of huge trees in the back gardens. Even in our tiny patch, it felt green and private.

As the area gentrified, gardens were re-designed for sun-loving plants. The trees vanished (in spite of their preservation orders). By the time we left London, we were all gazing into each other’s back windows.

How to prune garden trees the 'transparent' way

This acer would still shield an over-looked garden, but you can see that the pruning allows  some light through

And trees are expensive

A mature tree takes at least twenty years to grow. Some are best at thirty or forty years old. If you regret cutting down a forty year old tree, you must re-plant and wait thirty-plus years.

Or you could pay for a mature tree, in which case, you’ll be seeing a large dent in your bank balance. Think thousands – or even tens of thousands. (If you are thinking of buying a new tree for privacy, check out my 8 best perfect-for-privacy garden trees for affordable ideas.)

Transparent pruning conifer

Mature trees cost thousands to buy, and they may not adapt well to moving. And  you couldn’t buy anything like these towering conifers at Vasterival. Transparent pruning means they do let light through, and the garden has year-round floral colour.

Why ‘transparent pruning’ could be the answer

‘Transparent pruning’ is a French technique masterminded by Dominique Cousin at Les Jardin des Vasterival in Normandy. Trees and shrubs are pruned by thinning out branches carefully. This allows light and air through, giving them shape and elegance.

How to prune garden trees for privacy and light

Posy and I signed up for his one day course at Vasterival, even though it was in French. Posy renovates and restores gardens (many of them middle-sized). Reconciling over-grown, congested trees with the need for privacy is a major issue for many of her garden clients.

French gardening trip kit

Posy and I set off to Normandy with our secateurs, French dictionary, gardening hats and a thermos.

We got a bit lost getting there…

After staying in a friend’s farmhouse nearby the night before, we set off to find Le Jardin de Vasterival. Luckily, we enjoyed seeing so many roundabouts twice, because the French plant their roundabouts well. (‘Oh, there’s that lovely dahlia combination again…’). At one point, we were delighted to u-turn and re-trace our steps, as it meant we could go back past a particularly good town square planting with rudbeckias, verbena bonariensis and white cleome.

French street planting of rudbeckia, verbena bonariensis and white cleome

This planting of rudbeckias, verbena bonariensis and white cleome looked stunning – I don’t think my photograph does it justice.

Vasterival is like the woodland gardens of Scotland and Surrey

Although Vasterival is far from ‘middle-sized’, it reminded me of woodland gardens in Surrey, and also of some conifer and rhododendron-based gardens in Scotland.

My parents’ garden in Camberley was three-quarters of an acre. It had an Edwardian planting style – rhododendrons, azaleas, camellias, privet and bamboo, with huge conifers towering over it. When the shrubs were in flower, it was magnificent.

Out of flowering season, it was a lawn surrounded by large, dark green lumps, under which even grass refused to grow. With such a heavy evergreen presence, it was hard to find the light for smaller shrubs, perennials and annuals.

However Vasterival, with its sweeping acres, has rich, green lawns under its ‘transparently pruned’ trees and shrubs. Dappled light comes through all day and there is the maximum chance of some overhead sun. The beautiful skeletons of the trees can be seen, and, all year round, other flowering plants grow at the trees’ feet or round their trunks.

Rosa glauca and sedum at Vasterival

In spite of Vasterival being a woodland garden, the ‘transparent pruning’ allows enough light for a wide variety of plants – here it is rosa glauca and sedum – to flourish.

My top ‘prune garden trees’ tip

Posy and I were able to learn to prune in French, because Dominique Cousin demonstrated while he spoke. My favourite tip was to avoid cutting branches short if a tree gets over-grown.

Find the bigger, older branches and cut them right back to the trunk, taking the whole branch out. If you cut a branch short, you just get alot of vigorous leaf activity and growth at the cutting point. The tree will become congested and your garden will be darker.

Dominique Cousin demonstrating transparent pruning

Dominique Cousin showing that if you cut a branch short, you will get alot of growth at the tip. But if you take the whole branch out from the trunk, then the effect is lighter and airier.

 And ‘lift your tree’s skirt’…

We noticed that many trees and shrubs at Vasterival were pruned to a skeleton at the bottom. Instead of foliage covering the lower branches, there were elegant ‘legs’. This, too, adds more light, creating space underneath where other plants can grow.

‘Lift its skirt’ was originally suggested to me several years ago by the talented illustrator and gardener, Hazel West-Sherring, when we were discussing what to do with a huge dark Leylandii in my garden which was usefully blocking a glaring street lamp. It was then a broad-based cone shape, but now we’ve cut off its lower branches, turning it into a lollipop. It is much less oppressive – while still performing its street-light blocking task.

Hydrangeas transparently pruned

These hydrangeas are ‘transparently pruned’ so that the flowers sit on branches which are bare at the base. This is perfect for the middle or backs of border and allows more planting around the base.

Leylandii lifted skirt

This Leylandii cyprus ‘Naylor’s Blue’ used to come down to the ground. If you follow the line of the upper branches you see that, as a cone, it covered the ground where the path now is. ‘Lifting its skirt’ has created a lot of space and light in my garden.

 How to train climbers up trees (so you can actually see them!)

I’ve often tried to train climbers up trees. The climbers disappear into the tree, then pop out in a great unreachable clump at the top. Then there is a fight to the death as to who will win – the climber or the tree.

‘Transparent pruning’ means that the base and lower branches of the tree are usually relatively clear. And the lighter canopy of leaves means that the plant can flower without having to get right to the top.

At Vasterival, Dominique Cousin trains hydrangeas, vines, clematis and many others into the trees. The climbers are pruned, too, so that their shape and their flowers can be seen – down at our level rather than high up in the air.

Hydrangea petiolaris and acer

Hydrangea petiolaris ‘Schizophragma’ showing off in the lower branches of an acer

A clematis growing round a bare conifer trunk at Vasterival

A clematis growing round a bare conifer trunk at Vasterival

So if you’re thinking of cutting down a tree…

…try thinning its branches or lifting its skirt first. And don’t forget that there are lots of plants that flourish in shade – you don’t need brilliant sunshine all day to have year-round flowers. Once you’ve cut the tree down, there’s no going back.

You can buy Dominique Cousin’s book, La Taille de Transparence (in French) on Amazon.

To improve your pruning with more expert tips – from Great Dixter in Sussex, see here. Good pruning will make your garden look so much lighter and prettier.

And do share this using the buttons below – you could save a few (potentially) beautiful mature trees from being turned into firewood. Thank you!

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