Pleached Trees; planting and support guide

As a garden designer, who specialises in awkward and overlooked gardens, I use pleached trees a lot in my designs. This is not because I'm lazy with my tree choice but because they really do offer a host of benefits to a small garden. Whether it's politely blocking out nosey neighbours, adding some contemporary drama or making the most of the space underneath them, pleached trees can bring the wow factor to any garden.

Pleached trees offer privacy and year-round interest in a garden, leaving space underneath for planting. Great for small gardens!

However, they are a bit of a diva when it comes to planting and staking. I think this is where most people get out of pleached trees and topiary. If you don't take the time to prepare them correctly your design concept will fall short. Badly supported or incorrectly planted trees mean you could be left with wonky donkey leaning trees. Don't be put off, a small amount of time in the preparation of your pleached tree planting will ensure years of beautiful symmetrical planting.

Pleached Tree Planting Guide

• What are pleached trees?
• Species of Pleached Tree
• How to plant pleached trees
• How to support pleached trees
• Tying in pleached trees
• Aftercare of pleached trees
• Advantages of Pleached Trees
• Drawbacks of Pleached Trees
• How and when to prune Pleached Trees
• Common Pleached Tree Problems

What are pleached trees?

A pleached tree is achieved by training a tree to a specific, usually rectangular or square, shape. Think of a cartoon or Lego square tree! The tree is allowed to grow on a main stem or trunk, with any lateral (side shoots) branches being removed before it reaches its ultimate height. Then, the laterals are allowed to grow out. The branches and subsequent laterals are tied onto a stable framework. Any branches that grow outside of this or contrary to the shape are pruned out before they turn woody. Keeping a really neat shape or habit. After a couple of years, you end up with a beautiful formal shape, a bit like a screen on a stem.

Species of Pleached Tree

Pleached trees come in a number of species, and there's plenty of variety to choose from. The most common varieties are:

• Oleaster (Elaeagnus x ebbingei) -like the ones in this guide
• Hornbeam (Carpinus Betulus)
• Beech (Fagus sylvatica)
• Holly (Ilex aquifolium)
• Red Robin (Photinia x fraseri)
• Cherry Laurel (Prunus laurocerasus)

How to plant pleached trees.

Pleached trees are planted in the same fashion as any container-grown plant, and the staking differs significantly. First things first, though!

1. Dig a hole that's 1.5 times the size of the original pot.

Loosen the soil in the base and around the sides of the dug hole and remove any debris from it. Work over the ground so it is broken up and will allow water to drain from it. Avoid adding compost or plant feed at this stage as it will simply slow down the rooting of the tree. If need be you can add mycorrhizal fungi to help root development.

2. Carefully remove the pleached tree from the pot 

Carefully lean the pleached tree on the inside, taking care that the frame is not damaged or bearing all of the weight on the ground. If need be, get a friend or partner to hold the canopy while you loosen the pot. Sometimes pleached trees are braced and stapled into the pot which needs removing first, this can sometimes be really delicate work!

3. Position the tree in the hole, then stand back

Make adjustments by adding/removing soil until the tree is level and true - sometimes, it's easier to have a friend help with the viewpoint when you adjust it. Keep standing back to make sure the top and sides of the frame are level. Nobody wants wonky pleached tree frames!

4. Backfill the planting hole whilst someone supports the tree

Backfill with the same soil - there is no need to add fertiliser or compost as this will just stunt initial root growth, which is needed for the tree to anchor itself over the next few years

5. Heel in the tree

Press down around the base of the tree and surrounding soil using your heel. This is known as heeling in. It helps to ensure the tree is firmly planted and won't blow over. Heel towards the trunk, pushing away from the tree. If you fail to backfill and compress properly, the tree will suffer from settlement, wind rock or failure to establish its root system.

6. Build a frame of supports for your pleached tree

See below for detailed instructions on how to brace and support your pleached trees.

How to support pleached trees

Making a frame for the pleached trees is necessary to ensure that they don't move or migrate over time. This happens particularly in exposed sites or where the soil may settle if air pockets give way. This is usually, if not completely, backfilled.

By creating a frame, you can ensure that the trees stay true to their clean lines and are stable as they are established in your garden or flower beds.

A solid framework for Pleached trees is essential to keep their uniformity.

The best method I have found over the years is to use a mix of fence post stakes and pressure-treated timber batons. I try to design my frame to be of minimal visual impact and try and mirror the positions of the tree trunks so it doesn't distract from the beauty of the trees. Obviously, it depends on the site, whether stakes can be placed where you want them, etc.! So don't beat yourself up if it's not perfectly symmetrical.

The key here is to make sure the support is solid and can hold the trees in their desired position.

Step 1: Hammer in some suitable tree stakes behind each pleached tree

Here, I'm using 2.4m stakes. You want to make sure they are in deep enough, so they don't wobble or move easily. There is no need to concrete them in or anything more drastic. A simple lump hammer should do the trick. I am using 5, given there are 5 pleached trees to support.

Step 2: Brace the stakes with pressure-treated outdoor timber

You need to brace the stakes horizontally using a piece of pressure-treated timber. You will need a spirit level, pencil, drill and suitable screws (such as decking screws).

For neatness, you want the brace just below the frame's bottom. This brace holds the stakes together as one unit, meaning that they completely support the trees, giving you a really stable, level frame.

Drill two pilot holes for two screws and then attach the first end of the brace. Then, use the spirit level mark on the other posts at the top of the brace. Drill pilot holes and screw each one in as you have the first. By the end, you will have a horizontal (hence the spirit level) brace across the back of your pleached trees.

Tying pleached trees to the supports

Now, here is the most important tip with any tree supports. You need to use a rubber or flexible tree tie. If you use string, wire or those cable ties you found in the garage, you're going to damage the tree. Potentially killing it over time.

If you look at quality pleached trees, the branches and supports will be tied with rubber strips. This allows movement, flexibility, and growth without cutting into the tree. If the tie cuts into the tree, it can cause irreparable damage to the water and food transport system, the lifeblood of the tree, causing it to die of thirst!

Why are rubber tree ties so good?

Well, rubber tree ties are great as they allow you to tie the tree, leaving enough flexibility for it to move slightly. You never want a tree to be entirely fixed; any severe wind will certainly damage it. Rubber tree ties also allow you to adjust them over time, usually to loosen them as the tree grows.

There are two parts to a rubber tree tie. The first is the solid loop that goes around the stake or support. Then, at the other length, the one with the slots in. This slotted length goes around the trunk of the tree, and the arrowhead fits back through the slots. You want it tight enough to hold it in place but not so it's strangled. Think as you would if you were tying a formal suit tie.

Aftercare of pleached trees

Once you have tied and supported the pleached trees, you need to give them a really good watering. Ensuring that over the next few weeks, you give them a good soaking at least twice a week, more frequently if the weather is warm and dry. This will help establish them in the ground. Keep checking the trees for any initial movement and tweak the ties if necessary.

With most pleached trees, you're required to prune them twice a year, usually in early spring and then late autumn when they are dormant. As a rule of thumb, I tend to trim off any shoots that grow past the frame or tie them into the frame to cover any gaps that may be there. It's really quite simple! If you need help with pruning I have a really speedy guide below to help.

Advantages of Pleached Trees

1. Space Saving: Pleached trees are ideal for small gardens or urban landscapes where space is limited. Their narrow, vertical growth habit allows them to provide height and structure without encroaching on valuable ground space.
2. Privacy and Screening: When planted in rows along property boundaries or around outdoor living areas, pleached trees form a dense, leafy barrier that offers privacy from neighbouring properties or unsightly views.
3. Architectural Interest: The carefully trained form of pleached trees creates a striking visual impact, adding a sense of formality and sophistication to garden designs. The precise lines and geometric shapes formed by the branches can complement modern or traditional architectural styles.
4. Seasonal Interest: Pleached trees can offer year-round interest depending on the species selected. Some varieties feature attractive foliage that changes colour with the seasons, while others produce showy flowers or ornamental fruit. Additionally, the sculptural silhouette of bare branches in winter adds structure to the garden during the colder months.
5. Versatility: Pleached trees are versatile landscaping elements that can be used in various ways. They make excellent formal hedges, allees, or focal points in garden beds. They can also be used to define outdoor spaces, create outdoor rooms, or frame views within the landscape.

Drawbacks of Pleached Trees

1. Maintenance: Pleached trees require regular pruning and maintenance to achieve and maintain their desired form. This includes annual trimming to shape the canopy and remove any unwanted growth. Without proper upkeep, pleached trees can lose their architectural shape and become overgrown.
2. Cost: The initial cost of purchasing pleached trees, especially larger specimens or those with intricate designs, can be significant. Additionally, professional pruning services may be associated with ongoing expenses if you lack the time or expertise to maintain the trees themselves.
3. Limited Selection: Not all tree species are suitable for pleaching, and certain varieties may perform better than others in specific growing conditions. As a result, the selection of trees available for pleaching may be somewhat limited, depending on factors such as climate, soil type, and desired aesthetic.
4. Establishment Period: Newly planted pleached trees may require time to establish themselves and fill out their framework. During this establishment period, the trees may appear sparse or less dense than desired, detracting from the overall visual impact until they reach maturity. They also need careful bracing as detailed above.
5. Space Constraints: While pleached trees excel at providing vertical interest, they may not offer as much horizontal spread or shade as untrained trees with a more natural growth habit. This can be a drawback when ample canopy coverage or shade is desired, such as outdoor seating areas or play spaces.

How and when to prune Pleached trees

Pruning or clipping pleached trees is essential to maintain their desired shape and encourage healthy growth. New gardeners can be a bit confused as to how to prune, and clip pleached trees. They need to be cut and maintained just like hedges to keep things simple. So, it usually requires cutting at least twice a year, in spring and autumn, or sometimes a third time if the season's growth is particularly vigorous!

Here's a guide on how and when to prune them:

i) Timing for Pleached Tree Clipping

Prune pleached trees during early spring before the birds nest and then again in autumn time. Which keeps them neat and tidy throughout the year. Avoid pruning during periods of active growth or hot, dry weather, as this can increase the risk of stress and disease.

ii) Tools for Pruning

Use sharp, clean pruning tools such as hand pruners, loppers, and pruning saws to make clean cuts and minimize damage to the tree. Always ensure the tools are sterilised before use. Disinfect tools between cuts, especially when pruning multiple trees, to prevent the spread of diseases.

iii) Pruning Technique

First, remove any dead, damaged, or diseased branches. Cut back to healthy tissue or the nearest lateral branch. Thin out overcrowded or crossing branches to improve air circulation and light penetration throughout the canopy. This helps prevent disease and encourages even growth. Trim back new growth to maintain the desired shape and size of the pleached frame. Focus on removing any vertical shoots that disrupt the horizontal structure.

If necessary, lightly trim the sides and top of the pleached frame to maintain a tidy appearance and encourage lateral branching. This keeps the pleached tree square. Avoid cutting into too much old wood or removing too much foliage at once, as this can weaken the tree and compromise its health.

iv) Maintenance

Regularly inspect pleached trees throughout the growing season for any signs of damage, disease, or unwanted growth. Perform light pruning as needed to maintain the shape and size of the pleached frame. This may include removing stray shoots or correcting minor asymmetries, especially if water shoots or shoots further down the clear stem emerge. Nip these off with secateurs.

v) Pleached tree pests and diseases

Monitor the trees for pests such as aphids, scale insects, or caterpillars and take appropriate measures to control infestations if necessary. Consider fertilizing pleached trees in spring or early summer to promote healthy growth and vigour. The best homemade organic plant feed is comfrey tea or peat-free compost.

Common Problems with Pleached Trees

Sometimes, no matter how diligent you are, your pleached trees may suffer from some problems or pests. If caught quickly, most of them can be rectified. Let me detail the common problems you may face with pleached trees. Problems with pleached trees can include pests, diseases, and environmental stressors. Here's a list of some common issues and their treatments:

A) Pleached Tree Pests

Aphids: These small insects feed on sap, causing leaves to curl and distort. Treat with insecticidal soap or horticultural oil.

Scale Insects: Scale insects can infest branches and leaves, sucking sap and causing yellowing or wilting. Apply insecticidal oil or systemic insecticides.

Caterpillars: Caterpillars may chew on leaves, leading to defoliation. Handpick caterpillars when feasible or use Bacillus thuringiensis (Bt) insecticide.

B) Pleached Tree Diseases

Powdery Mildew: Powdery mildew appears as a white, powdery coating on leaves and stems. Improve air circulation and apply fungicidal sprays containing sulfur or potassium bicarbonate.

Leaf Spot: Leaf spot diseases cause dark spots or lesions on leaves. Prune and dispose of infected foliage, and apply fungicidal sprays if necessary.

Anthracnose: Anthracnose can cause dieback and leaf blight. Prune affected branches and improve air circulation to reduce humidity levels.

C) Planting or Environmental Stress

Drought Stress: Adequately water pleached trees during dry periods to prevent drought stress. Apply mulch around the base of the trees to retain soil moisture.

Frost Damage: Protect pleached trees from frost damage by covering them with frost cloth or burlap during cold snaps.

Root Compaction: Avoid compacting the soil around pleached trees, as this can restrict root growth and lead to nutrient deficiencies. Use mulch and avoid heavy foot traffic around the root zone.

Wind rock or root lift: Usually when a tree hasn't been heeled in or braced correctly. Reheel it in and provide support if the tree becomes unrooted ASAP.

D) Pleached Tree Nutrient Deficiencies

Nitrogen Deficiency: Symptoms include yellowing leaves and stunted growth. Apply a balanced fertilizer containing nitrogen to correct deficiencies.

Iron Deficiency (Chlorosis): Leaves may turn yellow or pale due to iron deficiency. Treat with iron chelate or iron sulfate, applied as a foliar spray or soil drench.

Summary

So there you have it, a comprehensive guide to planting and supporting pleached trees. Pleached trees are a versatile and space-efficient addition to any garden, offering both practical and aesthetic benefits. Their vertical growth habit makes them ideal for small or urban gardens where ground space is limited while also providing effective privacy screening and noise reduction from neighbouring properties or roads.

With their formal and elegant appearance, pleached trees add structure and sophistication to garden borders giving a super modern look to your design. They offer year-round interest, from lush foliage in spring and summer to colourful autumn displays and architectural winter silhouettes.

Pleached trees can also be tailored to suit different design styles and preferences, making them a versatile choice for various garden settings. Additionally, when strategically positioned, they can provide shade during hot summer months while allowing sunlight to filter through in winter, optimizing garden microclimates.

Please comment below if you have any questions or on my YouTube channel for more help. I'd also love to see pictures where you have used pleached trees in your own gardening!

If you're a fan of pleached trees then why not Tweet, Facebook or Instagram me with your pictures? You can also follow me on Youtube where I’ve got plenty of garden guide vlogs.

Happy Gardening.

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