Leylandii – Your complete guide including growing tips, propagation and pruning

Leylandii – Your complete guide including growing tips, propagation and pruning

Leylandii – Your complete guide including growing tips, propagation and pruning

Leylandii – Cupressocyparis

Wthout doubt the most popular hedging plant available in the UK with over 55 million already planted in hedge rows and a staggering 300,000 trees sold every year. They are known for their very fast growing habit and make suitable trees for forming a hedge or screening. They can also be grown as an individual conifer where space allows (they need a lot of space) and the evergreen foliage and conical shape makes them very attractive, large compact conifers.

We have put this comprehensive guide together to offer valuable information to help you decide whether to plant leylandii and how to care for them as well as more detailed information from the history, growing care, propagation and avoiding, getting into disputes with neighbours.

See other fast growing hedging plants that might be suitable – click here

Our guide will cover the following points:

  • Brief history and ideal growing conditions
  • General planting guide & tips, trimming, pruning and propagation / taking cuttings
  • What they can be used for – ie: to reduce noise, screen off unsightly areas, forming large and small hedges
  • Height laws, why they cause disputes and what you can do about it

Leylandii pruning  to form a hedge is essential to maintain a control the hedge, trimming will be needed at least 3 times a year over summer is not a lot more regularly to control the leylandii growth rate

Brief History

Cupressus x leylandii and Leylandii cypress is more commonly known to most people as ‘Leylandii’. They are actually a cross of two types of conifer trees from North America called Monterey cypress and Nootka cypress that had been planted in Leighton Hall in Powys, Wales in 1845 by a rich banker.

Later in 1925 commercial nursery men were looking for a good fast growing hedging conifer that would grow tall and withstand the salty and windy locations of seaside areas. They then discovered what was 7 trees at Leighton Hall (6 of which are still standing today) and started to propagate these trees and it was not long before they were being sold and be came one of the best selling plants in garden centres and nurseries across the UK.

Growth rate – How fast do they grow?

They are the fastest growing conifer in the UK and will grow up to a 3ft (90cm) a year but they can easily be kept at 5ft (150cm) tall, or alternatively grown to any desired height you require them grow too. They can reach staggering heights of around 40 metres (130ft) high. When first planted, it usually takes the first 12 months to get the roots out and may not grow much in the first 12 months. After this period they will quickly establish so maintenance is essential to stop them getting out of control.

Growing Leylandii

An excellent plant to use as a living wall (hedge) despite the recent bad press. Like any other hedging plant it does need to be kept trimmed.

They are evergreen which means they don’t lose their foliage for the winter. They will grow in most well-drained soil types including chalk, clay, sandy or loamy soils in full sun or partial shade. They grow well in exposed windy areas or sheltered sites but in more exposed windy areas, very tall specimens have been known to topple over but if planted as a hedge up to around 10ft (300cm) this won’t be a problem.

The only conditions they won’t really enjoy being in is areas where the ground is constantly water-logged. Read further down to see how this can be overcome.

Uses

A great choice for forming a screen to provide privacy and screen off any unsightly areas such as industrial estates, motorways or anything you don’t want to sit in your garden and look at. They are also good for reducing wind and noise as well as increasing security as they grow tall. They provide a great habitat for local wildlife and birds. They can be used to filter our pollution from motorways.

Planting a Leylandii hedge

Planting a hedge is very easy and simple to do, if you follow our guide you will have a healthy established hedge in no time.

They are best spaced approximately 18 inches to 24 inches apart to form a hedge approximately 5 to 10ft tall. If you are going to grow your hedge to over 10ft you will get away with spreading them around 1 metre (100cm) apart.

Generally the smaller the plants you plant the better hedge they will form sooner.

  1. Ground preparation: They need well-drained soil to thrive so if the area where you are planting the hedge is particularly wet and holds water you will need to resolve this problem first. If the area does hold water but it does drain away within a few hours then simply digging in some horticultural grit and organic matter may be enough to improve drainage. If you have a very wet area then you may need to add drains or a soak-away to drain the water away.
  2. There are two ways to plant a hedge, you can simply space your Leylandii out 18″ to 24″ apart and dig the holes twice as wide and deep as the roots of the trees or dig a trench the length of the hedge. There are no right or wrong ways but sometimes it is easier to dig a trench.
  3. Mix some good quality compost and farm manure into the pre-dug holes or trench and mix well with the soil at the bottom of the holes/trench. Ensure farm manure is well mixed with the soil as it is very rich and can damage roots if not mixed in well. You could add some 12 month fertilizer granules (osmocote) to the soil to improve the soil nutrients but this is not essential.
  4. Place the trees in the holes/ trench and back fill the surrounding soil back into the holes/trench around the roots and firm with your foot. Ensure you plant them no deeper than the original depth they were planted in the pots. Planting them too deep can kill the plants if the soil is up the stem too much.
  5. Water regularly and do not allow them to dry out, remember that if it rains they don’t have established root systems so may still need watering. This is a common mistake many people make which leads to plants dying.
  6. Stake plants to ensure they do not fall over and push stakes right into the ground deeper than the roots. Check plants regularly after windy conditions to ensure they are not leaning over and firm again if they have moved or become loose.

Pruning

When to prune

Leylandii are fast growers and as such need pruning (trimming) at least once a year. We do recommend trimming them two or three times a year to keep them looking well and it is usually easier this way with less clippings to recycle. If you have just planted a hedge, you will want to let them grow to your desired eventual height. Once they reached this height you can then cut off the tips at this height. This will then encourage them to bush out at the base of the trees and start to fill out to form a solid hedge.

Ideally you want to trim your hedge in spring and summer and not too late in the season as this way the new foliage produced in late summer will give the hedge some protection over winter. Never cut too far, to a point where the hedge is brown as they do not recover and do not regrow from the brown bark. This is why you see brown hedges, they have usually been pruned too hard at some point and didn’t recover, usually after been left too long before trimming. Ideally hedges like this need replacing.

Remember it is easier to prune a hedge once or twice a year than it is to let it grow for a few years and try and prune it down by 5ft which may need specialist equipment and be costly. It also leads to hedges going brown as explained above.

Consider using a long reach hedge trimmer to make trimming your hedge easier, you can also put the trimming through a garden shredder and the chipping can be composted down or used as a mulch.

See our reviews on the best garden shredders

See our reviews on the best garden incinerators

Do the roots damage buildings?

They are shallow rooted, and as such do not cause much concern when planting near buildings as some might think. The roots will grow to a similar height of the tree, this means if you keep your hedge to a reasonable size such as 6ft then the roots will likely only grow to a similar size. Many people think that the roots will damage building foundations but in reality the problem is not that the roots damage foundations but that on wet clay soils they can take up water causing the soil to shrink which can cause subsidence and in the same way removing them can cause the ground to swell causing similar issues.

Most properties will not be affected by this and it is usually homes that were build before the 1950’s as they have foundations that are only 50cm (20in) deep.

Taking cuttings

To propagate leylandii, the easiest way to do this is by taking a semi-hardwood or hardwood cutting, both are taken in the same way. Semi-hardwood cuttings are taken late summer and are taken from the current seasons wood that is not quite mature and hardwood cuttings are taken in autumn and winter from established growth from the current year.

All you need is a sharp cutting implement such as secateurs or a knife, suitable pot, some compost and sand and some rooting powder to encourage the root growth.

Take your cuttings from the ends of the branches and choose healthy growth that is approximately 6-12inches long. Make a neat cut just below a bud and remove a third of the foliage from the bottom of the cutting.

leylandii prunings ready to remove the lower foliage

leylandii cutting ready to plant

Dip the cutting into rooting powder and make a small hole in a suitable pot and insert the cutting. The compost needs to be a mix with sand to improve drainage. Mix compost and sand 50/50.

leylandii cutting rooting powder

mix compost and sand 50/50 to improve drainage

Take more cuttings than you need as they won’t all grow. Water well, and put in a light space outside but not in direct sunlight.

leylandii cutting potted

Your cutting should start to show roots in spring and can be potted on into small 9cm pots and grown on for a few months. They will fill the pots quickly and can probably be planted out in summer when they have sufficient root systems.

For a more in depth look into taking cutting click here

Height laws

Everyone has the right to plant a hedge and you do not need planning position in most cases. As long as you keep your hedge no taller than 2 metres (approximately 6.5ft) then usually you will have no issues and the council cannot take action against you.

However they have been the cause of many arguments with neighbours and in 2005 it was estimated that 17,000 people were in disputes with neighbours over tall hedges. They are usually caused because of tall over-grown hedges which can lead to lack of light, restricted views and damage to neighbouring gardens and properties.

Due to this problem in 2005, the government introduced Section 8 of the Anti-Social Behaviour Act (2003) to cover tall hedges and gives the councils the right to make homeowners reduce the heights of hedges if “the hedge is adversely affecting the complainant’s reasonable enjoyment of their property”. If you file a complaint with the local council they do charge to intervene so try to resolves issues yourself first. They will also not intervene if you have not tried to resolve the issue by talking to your neighbour first.

There is no specific legal height for how tall the hedge can be and they will only get involved under the following conditions:

  • The hedge is over 2 metres tall (approximately 6.5ft)
  • The hedge is made up of 2 or more evergreen trees (single trees are not covered)
  • The hedge is affecting a domestic property
  • You have tried to resolve issues yourself, keep records as proof as the council won’t act if you don’t.

See the official government page regarding this by clicking here

How to avoid future problems

  • We recommend that if you intend to plant a hedge that you let your neighbour know your intentions. How tall you are going to let it grow to and that you will trim it regularly to keep it under control.
  • Keep the hedge to a reasonable height ie: 6ft (180cm) tall or smaller
  • Have consideration for your neighbours when planting hedges.
  • Discussing it with your neighbour is usually enough to avoid any problems in the future.

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4 Responses to "Leylandii – Your complete guide including growing tips, propagation and pruning"

  • I have bought three Leylandii of about twelve feet and several more of 5-6 feet. Will they all need to be staked?

  • Yes, I would strongly recommend you stake them. The stakes are more for support to stop them moving around or blowing over.

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