Horticulture Magazine

Leylandii

a wall of leylandii hedging
By APRIL FOOT
April Foot, BA (Hons) - Gardener

April is a writer specialising in gardening and the environment. She is an avid wildlife-enthusiast and adventure-seeker, and feels happiest when in the Great Outdoors. April graduated from the University of Southampton in 2013 with a BA (Hons) degree in English.

/ Updated July 3rd, 2023
Reviewed By COLIN SKELLY

Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.

/ Meets Our Editorial Guidelines

The Leylandii (x Cuprocyparis leylandii) is a fast-growing, evergreen conifer that makes up much of our British hedgerows, and divides many a garden – and opinion.

A UK-born hybrid of the Monterey cypress and Nootka cypress trees, Leylandii is a hardy plant which grows quickly and easily in the UK and thrives in a wide variety of soils.1Leyland Cypress (Cupressus x leylandii). (n.d.). Woodland Trust. Retrieved March 21, 2023, from https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/leyland-cypress/

When properly pruned and managed, it makes the ideal hedgerow or screen – dense, green, and capable of reaching great heights.

multiple cypress hybrids in a row with a brick wall in the background and flowering plants in the foreground

Many people admire Leylandii for its impressive size and foliage, which can provide shade and shelter, and create a feeling of privacy in even the most overlooked gardens.

But it’s not for everyone – this thirsty tree consumes a lot of nutrients from the soil, and can block out much-desired sunlight.2BBC. (2006, October 23). Ask the gardener: Hedges. Retrieved March 21, 2023, from https://www.bbc.co.uk/lancashire/content/articles/2008/01/08/hedges_feature.shtml

Leylandii is responsible for more than its fair share of neighbourly disputes!

Providing you know what you’re getting into, Leylandii can make a highly advantageous addition to your garden.

Overview

Botanical NameLeylandii
Common Name(s)Leyland Cypress
Plant TypeTree
Native AreaNorth America
Hardiness RatingH6
FoliageEvergreen
When To SowMarch, April
When To PruneMay, June, August, September
Sunlight

Preferred
Full Sun / Partial Shade

Exposure
Exposed or Sheltered

Size

Height
12M+

Spread
4 – 8M

Soil

Preferred
Most Soil Types

Moisture
Well Drained

pH
Any

Leylandii is said to have originated on the Leighton Hall estate, near Powys in Wales.

Here, the Monterey cypress and Nootka cypress trees, which are both native to North America and usually grow 400 miles apart, were brought into contact for the first time.3Taxodium distichum. (2019). The University of Texas at Austin. Retrieved March 21, 2023, from https://www.wildflower.org/plants/result.php?id_plant=tadi2

They were cross-fertilised, creating 6 clone plants, and the Leylandii (or Leyland Cypress) as we know it today was born.4Types of Leylandii. (2021, September 24). Leylandii.com. Retrieved March 21, 2023, from https://www.leylandii.com/types-of-leylandii/

towering leylandii trees sit behind a large stone fence as a huge garden boundary

Leylandii is a fast-growing, pyramidal conifer that can reach over 30m tall.

It has reddish-grey ridged bark, and brown slender twigs – although these are mostly concealed by the dense green foliage.

This foliage consists of scaly, over-lapping leaves in flat sprays.

leylandii conifer with light green foliage

The tree also produces ball-shaped brown cones, which on male plants have yellow tips at the end.

Common Varieties

The two most common variants of Leylandii are Green and Golden – of these, the green variant is the most common.

It grows faster and taller than the gold, and its leaves are finer, scalier, and more blue-green in colour.

In comparison, Golden Leylandii leaves are, unsurprisingly, gold-tinted.

Within each variant are many different cultivars, including the bright green ‘Hillspire’, the blue-tinged ‘Naylor’s Blue’, and the yellow-tipped ‘Gold Rider’.

Close up of leylandii foliage
Leylandii has stunning green and yellow foliage

As is common in hybrid plants, Leylandii is sterile and is not capable of reproducing itself.

This means that all of the numerous Leylandii plants growing in the UK today were planted by humans.

Leylandii’s popularity stems from its dense foliage, inexpensive cost, and quick-growing nature (it can grow around 1m every year).

The thick, evergreen foliage ensures it looks good year-round and can provide effective shade and shelter from the elements, as well as a privacy screen between gardens, a barrier against noise pollution, and a home for wildlife – it’s great for encouraging more birds into your garden.

Plant Care & Growing Tips

Soil Requirements

The Leylandii is a hardy plant and will grow in many types of soil.

However, Leylandii plants need a lot of nutrients and will drain your soil dry.

In order to compensate, you will need to add a lot of compost or rotted manure, to replace the nutrients – the best times to do this are spring and autumn.

Watering

tall cypress hybrid conifers planted in a row for hedging

Similarly, Leylandii also has a high water requirement, and you should water it regularly with your garden hose whilst it’s growing.

Once established, it is more tolerant to periods of drought, however, you should still water it to achieve the best growth.

Leylandii does not like waterlogged soil, so make sure the area has good drainage.

Full sunlight is preferred, but it will also grow well in partially shaded areas.

Planting

The best time to plant Leylandii is in spring or summer.

Dig a hole twice the size of its root ball system, and place the Leylandii in the hole, ensuring that the top of the root ball is no more than 1cm below the top of the soil.

Add potting soil to the hole to give the plant a nutrient boost, and pack the soil down. Water until it is moist, but not saturated.

small leylandii tree in a rectangular upright planter and painted white wall in the background

In order to grow Leylandii as a hedgerow, you should position the young plants approximately 1m apart from each other (and a reasonable distance from any buildings).

Keep them well-fed and watered, and within 3–4 years, they should grow into each other and form a hedge.

Trim it regularly to keep it under control, and in the desired shape (see more on pruning below).

many leyland trees planted in black plastic pots

Due to its high nutrient and water needs, it can be difficult to grow other plants around your Leylandii.

If you want to do so, you’ll need to choose hardy varieties that can cope with impoverished soil.

Some good examples of ground-cover plants that can grow around Leylandii include periwinkle (Vinca minor), bergenia, and Welsh poppies.

Habitat & Growing Conditions

As the Leylandii is technically native to the UK (being the child of two American trees, but ‘born’ over here), it is tolerant of our seasonal climate, including wind and cold temperatures.

It can grow in sunny and partially shaded areas, sheltered or exposed, and will withstand temperatures between -25-30°C.

semi detached homes in winter with hedging in the front garden and a 'sold' sign out front

As far as soil goes, Leylandii isn’t too fussy there either and will grow in everything from sandy, clay or chalky soil – as long as it is moist.

However, it doesn’t like waterlogged ground, as this can cause root rot, so the soil must have sufficient drainage.

It is happy in both acidic and alkaline pHs.

Pruning Leylandii

Regular pruning of your Leylandii is essential – this is an especially fast-growing plant, and once it grows too tall, it can become very difficult to trim back.

Neglected Leylandii can quickly become a source of neighbourly tension!

Pruning too much at once can also mean the plant won’t regrow, causing a brown patch, so it’s best to keep on top of it.

lenylandii hedge being cut back with manual trimmers
It’s important to regularly cut back your hedging

You should aim to prune your Leylandii twice a year (or more if required), to keep it at the desired shape and height.

Aim for a height of around 2m, as this will ensure you can easily maintain it, and keep it looking its best, with even foliage throughout the plant.

If your Leylandii grows too tall, it may not be able to get enough nutrients from the surrounding soil, and the lower branches may shed their leaves.

It’s also important to note that trimmed old wood will not grow new leaves, so you want to make sure you’re cutting new green shoots, as well as removing any dead branches – and the way to do this is by regular trimming.

leylandii trimmings in a large yellow refuse sack

A good time to prune is in late spring/early summer, and then again in late summer/early autumn.

Providing your Leylandii is within your reach, there’s no reason you can’t prune it yourself using pruning shears.

Otherwise, you may wish to employ the services of a professional tree surgeon.

If you want to significantly cut back or fell a Leylandii that’s near your home, you will probably need to do this in stages (a tree surgeon will be able to advise).

an evergreen leylandii garden hedge

Gradual cut back will allow the surrounding soil to adjust to the higher water content as the Leylandii consumes less, and will prevent soil heave, which can cause damage to buildings.

Where To Buy Leylandii

Leylandii is one of the most commonly purchased plants in the UK, and is available from numerous sources.

You can buy it from garden centres, specialist growers and online suppliers.

Common Problems

Leylandii is susceptible to canker disease and blight.

Kabatina Shoot Blight

One such example is Kabatina shoot blight, a damaging fungal infection which causes foliage to turn brown, and eventually grey, and needles to drop early.

dying hedging with visible brown patches

If your Leylandii is struck by this, prune the infected branches, apply a copper fungicide, and give it plenty of food and water to enable it to fight the disease.

If this doesn’t work, you will have to remove the plant from the hedgerow.

Honey Fungus

Another fungal infection to watch out for is honey fungus.

This deadly fungus spreads underground, and attacks the roots of the Leylandii plant, causing them to die and decay.

Symptoms include leaves turning pale and dying, a white layer of fungus in the bark at the base of the plant, and honey-coloured toadstools appearing in the autumn.

There is no cure for honey fungus – an infected plant must be removed and destroyed, and a physical barrier created to avoid it spreading to neighbouring plants.

Pests

Common Leylandii pests include bagworms, scale insects and conifer aphids.

magnified view of gall aphids on a conifer

Aphids (greenflies) can affect your Leylandii’s growth, sucking its sap and excreting a sticky residue (honeydew), which can make it vulnerable to mould.

Signs that your Leylandii is affected include visible bugs, honeydew and distorted leaves.

Infestations are usually controlled by natural predators in summer.

Neighbourly Disputes

The biggest problems faced by Leylandii owners occur as a result of the plant growing too tall and out-of-hand, particularly in residential locations.

Leylandii can often cause unwanted shade and needle-dropping in surrounding gardens, leading to disgruntled neighbours and neighbourly disputes.5Our least popular export? (2014, September 24). BBC Gardening. Retrieved March 21, 2023, from https://www.bbc.co.uk/shropshire/content/articles/2005/06/06/garden_leyland_feature.shtml

If you’re considering planting Leylandii, and you have close neighbours, you should always be considerate.

a large landscaped garden with rose arch, tree saplings and a large surrounding leyland hedge as a garden border

Ensure your hedge is kept well-trimmed, so it doesn’t encroach on your neighbour’s garden, and ideally less than 2m high, so that it doesn’t block out light.

If any part of your hedge crosses the boundary into a neighbouring garden, your neighbour has a right to trim back that part.6High hedges – neighbour disputes. (n.d.). Leeds.Gov.uk. Retrieved March 21, 2023, from https://www.leeds.gov.uk/planning/high-hedges-neighbour-disputes

If a neighbour believes your Leylandii is damaging or affecting their enjoyment of their property, they can also put in a complaint to the council.

How To Stop Leylandii Growing

Leylandii is a hardy, fast-growing plant that can quickly grow out-of-hand – un-trimmed trees have been known to reach over 30m tall, and 8m wide.

The only real way to stop a Leylandii growing is to kill it, or remove it from your garden.

If you need to stop Leylandii by removing it, it would be best to enlist the help of a tree surgeon, who can advise on the best course of action.

This may involve cutting the tree down gradually, to allow the surrounding soil time to adjust, and avoid soil heave.

freshly trimmed hedging and blue sky with clouds

The best way you can prevent Leylandii growing too high is by regular pruning.

As long as you do this 2-3 times a year, and cut it back enough each time, you shouldn’t need to worry.

“As a quick-growing hedge, you can’t ask for better than Leylandii but, unless you want to fall out with your neighbours, be prepared to cut it back several times a year to keep on top of it because if you can’t cut back into the wood, it will have a tendency to increase in size year-by-year,” shares Master Horticulturist Colin Skelly.

“If you have the space (lots of it) you can let it do its thing and allow it to grow into a specimen tree.”

Aim to keep it below 2m tall, so you can easily maintain it – and keep your neighbours happy.

References

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