This month we offer advice on using pleached trees for garden screening – and pick our favourite plants…
If there’s one design element we are most frequently asked to create in our Cambridgeshire gardens, it’s screening.
Whether it’s to hide ugly objects such as trampolines and compost heaps from view, or interrupt views from nosy neighbours, everyone wants their garden to be a private paradise – and screening can do the job nicely.
Walls and fences can be an expensive and very permanent installation – with the harsh façade often calling for concealment itself – while fast growing trees and bulky hedging plants can get out of control, cast shade and eat into valuable ground in a small garden.
At Abbotswood, we’re big fans of pleached (also known as espaliered) shrubs and trees, which create living walls of natural foliage. These so-called ‘tall borders’ and ‘green screens’ are essentially lines of trees tied into a climbing frame, and clipped to form a flat “hedge on stilts” above bare trunks.
In our age of tower block skyscapes, trained trees can be very useful – providing height at a price that’s not as prohibitive as brick (and won’t resemble HM Pentonville), and they help to blur boundary lines and create privacy without blocking out valuable light. They also provide a haven for wildlife, which brings its own liveliness to the garden.
Pleached trees are nothing new of course; in fact it’s thought this formalised hedging was used as a ‘defensive barrier’ against invading armies in the time of Julius Ceasar. Battlements aside, many landscape architects of the 17th and 18th centuries continued to use pleached trees to create living fences, which defined views and created intimate rooms. Pleached limes were particularly prevalent in the French ‘grand allées’ of the 19th century.
But thanks to a recent revival, particularly among Chelsea Flower Show designs, trained trees are no longer associated with just the grand schemes – they can be eye-catching structures for the smaller garden too. And such is their renewed popularity, you can buy them ‘ready made’ to slot into your garden like fencing panels.
There’s a huge range of these ready-made pleached trees on offer, from Acer campestre to Liquidamber styraciflua, and the espaliered forms are the finest quality. Rather than being grown tightly on panels, they are tiered like the espalier pome fruit forms. We’ve pruned some wonderful lime trees grown this way and it is possible to graft neighbouring trees together to form a continuous block.
Practice what you pleach
Grow them yourself, however, and you can save a lot of money and be more flexible about their proportions.
While they are easy to plant and establish, any pleached tree, by its very nature, will require a good deal of pruning. Examples of non-pruned trees abound around Cambridge and I can vouch that the unkempt forms are not very attractive!
It’s also possible to pleach trees on the horizontal plane, and create ‘parasol’ forms with a square flat head on a standard. Many plants lend themselves to this style including Tillia x europea ‘Pallida’, Parrotia persica, Platinus x acerifolia and Morus platinifolia.
To grow your own, first get the support system in place. This needs to include two sturdy uprights at each end with horizontal wires between the posts, with the lowest at the level you need the foliage to start. How many wires you use depends on the thickness and height of your space. You can also use bamboo frames.
Create planting holes twice the size of the root balls and set your plants around 2-3m apart, securing them to stakes. Tie in any horizontal braches there and then, and train the rest as they grow.
In July, and the following winter, you can tie in the leading branch and prune any others that point straight out or in the wrong direction. Secure any branches that are naturally horizontal (don't force them into place) and ensure twine ties are not too tight that they bite into the tree flesh.
Each year, you’ll want to prune and clip in the same way to keep the shape sleek and compact. They will grow up and out so ensure they’re planted in a position where you can get to them from all sides.
Pleaches and cream: our favourite plants for pleached panels
- Sweet chestnut holly (Ilex castaneifolia)
Plenty of vibrant red berries in autumn. It tolerates shade so is a good choice for a north-facing garden.
- Holm Oak (Quercus ilex)
Attractive, glossy-green, evergreen leaves with a pale grey back, and edible acorns in winter. It prefers a well-drained spot.
- Crab apple (Malus Evereste)
Pretty and productive, this lovely ornamental fruit tree has white flowers in spring and small orange fruits in autumn, which make excellent jelly.
- Hornbeam (Carpinus betulus)
We’ve used Carpinus betlua on the terrace at a design in Windlesham and they are stunning in a courtyard garden setting. Even though they are deciduous, they can create year-round screening thanks to the way they cling on to their coppery leaves and create a dense thicket of stems.
- Lime (Tilia x europaea ‘Pallida’)
Gorgeous green-yellow foliage and autumn colour as well as sweetly scented flowers.
- Honey Locust (Gleditsia triacanthos ‘Sunburst’)
A small tree with fabulous, feathery golden leaves in spring, turning lime green in summer. Shade tolerant.
- Callery Pear (Pyrus chanticleer)
Deciduous tree, which has beautiful blossom (followed by green brown fruits) and retains its leaves until mid winter.