Green Leylandii (x Cuprocyparis leylandii or Leyland Cypress) is the quickest growing conifer in the UK. It will form a hedge faster than any other evergreen plant and, if it is trimmed once or twice a year, it can kept to any height or shape. Where space allows, it will form an elegant columnar tree of dense foliage.
Green Leylandii is quicker growing than the Golden Leylandii and will form a dense evergreen hedge of any shape or size if it is looked after from the start.
Green Leylandii is a hybrid cross of two conifers, the Nootka Cypress (Chamaecyparis nootkatensis or Xanthocyparis nootkatensis) and the Monterey Cypress (Cupressus macrocarpa). These trees are native to different parts of the USA. The trees were brought to the UK & Ireland by plant hunters and planted close together where they formed the cross x Cuprocyparis leylandii.
Leylandii gets its name from C J Leyland who grew seed from a Nootka Cypress growing at Leighton Hall in Wales in 1888, with a Monterey Cypress as its male parent. Six plants were raised and were originally named Clones 1 to 6. They were called clones becaused they were propagated by taking cuttings so the genetic material was identical to the parent. Some of best clones were given proper names such as "Leighton Green", "Haggerston Grey" and "Naylors Blue". The different types of Leylandii are also often called "cultivars".
Twenty or thirty years ago most growers of Leylandii knew which clones/cultivars of Leylandii they were growing. Now, most growers are unaware of the exact clone they are growing. Many may well be growing a mixture of clones. Haggerston Grey and Leighton Green are probably the most widely available clones in commercial production. To the layman's eye, the commercially available clones are very similar and will all form a good hedge. In general, it is just sold as "Green Leylandii", the main exception being the recent introduction of the clone "Leylandii 2001". This has a distinctly different habit of growth (see below) and so is sold as a separate form.
For a list of other cultivars of Green Leylandii, see below.
Below is a list of Green Leylandii. Please bear in mind that most of these are not available commercially and that usually Leylandii is just sold as Green Leylandii. All clones will form a good hedge if they are planted well and trimmed properly.
Leyland Cypresses are divided into two different types: those clones with"angular plumose" foliage and those with "flat-pinnate foliage". Those with angular plumose foliage are similar to, but not exactly like, that of the the parent Cupressus macrocarpa (Monterey Cypress). They have side shoots that lay in several planes, particularly two at right angles. The flat-pinnate foliage is similar to Chamaecyparis nootkatensis in that its side-shoots arise and lay predominantly in a single plane and are regular, parallel and symmetrical, giving the whole shoot the flat-pinnate form of a fern-frond (Ovens, Blight & Mitchell, 1964).
A form of Green Leylandii with flat-pinnate foliage, similar to Leighton Green. Probably the first incidence of the cross between a Nootka Cypress and a Monterey Cypress. Bears cones readily when young. There is some evidence that the female parent was the Monterey Cypress and the male parent was the Nootka Cypress, although the evidence is not conclusive.
A form of Green Leylandii with angular plumose foliage. One of six seedlings to be raised from seed taken from a Nootka Cypress at Leighton Hall with a Monterey Cypress as its male parent. Very similar to 'Haggerston Grey'.
This is probably the most common for of Green Leylandii available in the UK. It has angular plumose foliage and was one of six seedlings to be raised from seed taken from a Nootka Cypress at Leighton Hall with a Monterey Cypress as its male parent.
Forms of Green Leylandii with angular plumose foliage. These three are from the six seedlings to be raised from seed taken from a Nootka Cypress at Leighton Hall with a Monterey Cypress as its male parent. They were not widely propagated from and are only found at Haggerston Castle in Northumberland. Very similar to 'Haggerston Grey'.
A form of Green Leylandii with flat-pinnate foliage. One of six seedlings to be raised from seed taken from a Nootka Cypress at Leighton Hall with a Monterey Cypress as its male parent.
A form of Green Leylandii with angular plumose foliage. One of two seedlings to be raised from seed taken from a Monterey Cypress at Leighton Hall with a Nootka Cypress as its male parent.
A form of Green Leylandii with flat-pinnate foliage. Probably the second most widely grown cultivar of Leylandii. One of two seedlings to be raised from seed taken from a Monterey Cypress at Leighton Hall with a Nootka Cypress as its male parent. Bears cones readily when young.
A form of Green Leylandii with angular plumose foliage. One of two seedlings grown from seed collected from a Monterey Cypress in a garden near Ferndown in Dorset, UK, although no Nookta Cypress could be found in the area. This cultivar was grown successfully in the UK for a number of years before it was shown to be susceptible to drought in the 1970's. As a result, it is not grown commercially any more.
A form of Green Leylandii with flat-pinnate foliage. One of two seedlings grown from seed collected from a Monterey Cypress in a garden near Ferndown in Dorset, UK, although no Nookta Cypress could be found in the area. This cultivar is not grown commercially any longer.
A form of Green Leylandii with angular plumose foliage. Much more upright than Haggerston Grey and Leighton Green, needing less support when young. Also denser in habit and more like a flame-shaped specimen conifer than a hedging conifer although will trim to form a good hedge. Foliage colour has a slight blue tinge. Becoming more popular and more widely available commercially. It is unknown if it is a branch sport of another cultivar of Green Leylandii or a new cross altogether.
Olive's Green is a branch sport of the 'Castlewellan Gold' and has the same habit of growth. It has angular plumose foliage. The foliage colour a soft, dull green.
A green form of Leylandii similar to Leylandii 2001. It is unclear whether this is a branch sport of Leylandii or a different cross altogether. Thought to come from INRA (The French National Institute for Agricultural Research).
A green form of Leylandii similar to Leylandii 2001 but with a very slight blue/green appearance. Occasionally found in commercial production.
A green form of Leylandii with a similar habit of growth to Leylandii 2001 but said to be more compact in growth. Not found in commercial production in the UK.
Listed by the Hillier Manual of Trees & Shrubs as the first dwarf Leyland Cypress. Generally weak in growth and susceptible to cold winters and hot summers. The most recent listing of any nursery growing the cultivar in the RHS Plant Finder was in 2005.
There are only a few clones of golden leylandii available commercially. Castlewellan Gold (x Cuprocyparis leylandii 'Castlewellan Gold') is by far the most common form of Golden Leylandii. 'Gold Rider' is often found commercially available and 'Robinson's Gold' and 'Excalibur' are difficult to find but can occasionally be found commercially available.
Leylandii Castlewellan Gold makes an excellent hedge if it is trimmed regularly (once or twice a year). It can be kept to any height and pretty much any shape. It is often used for topiary. Its young spring and summer growth is a bright golden-yellow colour that turns to a green-gold in autumn and bronzy-gold in a hard winter.
Castlewellan Gold (sometimes called 'Galway Gold') was first raised as a seedling at Castlewellan, Co Down in Northern Ireland in 1962. It is a cross between two conifers. The female parent was Cupressus macrocarpa 'Lutea' and the male parent was Chamaecyparis nootkatensis 'Lutea'.
Leylandii 'Gold Rider' was raised from a sport* in Holland in the 1980's. It has angular plumose foliage and looks like a sport of Haggerston Grey as it has a very similar habit of growth. It is a brighter gold than Castlewellan, Robinson's Gold or Excalibur and holds its colour well throughout the year. It is slower growing than Castlewellan Gold and as a result is less popular as this makes it more expensive to produce and it takes slightly longer to form a screen. Forms an excellent hedge. Its bright golden foliage is best in full sun. Growth rate up to 2ft per year.
A golden form of leylandii with flat-pinnate foliage. Slightly brighter gold than Castlewellan and Excalibur but not as bright as Gold Rider. Very similar to 'Leighton Green' in habit of growth. All plants are from a seedling raised at Belvoir Castle, County Down and named after Mr Robinson, the Head Gardener who found the minute seedling growing among some Rhododendrons that were being cleared.
A golden form of Leylandii very similar to 'Castlewellan Gold' but with denser growth and looking more similar to Cupressus macrocarpa Goldcrest. Believed to be a branch sport of Castlewellan developed at Deeping Gate Nurseries Ltd in Peterborough, UK. Plant Breeders Rights are applicable to this cultivar so it can only be propagated under licence.
This golden form of Leylandii is virtually identical to Castlewellan Gold and The Hillier Manual of Trees & Shrubs lists it as another name for 'Castlewellan Gold'. Indeed, many growers are growing it as Castlewellan Gold and it is not usually found available as 'Galway Gold'. However, research on the DNA of Leyland Cypresses by Adams, Rushforth and Trimble in 2006 did show that it is distinct from 'Castlewellan Gold' in it's DNA structure. However, effectively it is now grown as 'Castlewellan Gold'
A golden form of Leylandii raised from a branch sport of 'Haggerston Grey' by Mr D F Wynant of Wyboston, Bedfordshire, UK. Said to be a brilliant gold in colour but for some reason it did not suceed commercially, perhaps superceded by 'Gold Rider'. Last listed in the RHS Plant Finder in 1997.
A golden form of Leylandii raised from a branch sport of 'Haggerston Grey' with angular plumose foliage, arising at Barnham Nurseries, Bognor Regis, Sussex, UK. No longer listed in the RHS Plant Finder.
A golden form of Leylandii raised from a branch sport of 'Haggerston Grey' with angular plumose foliage, arising at Pickering in Yorkshire. Raised by Mr Stephen Smith. No longer listed in the RHS Plant Finder.
There are a few cultivars of variegated leylandii but most are very difficult to find commercially and have never really been popular with gardeners.
A variegated form of Leylandii arising from a branch sport of a Haggerston Leylandii at Weston Park, Staffordshire, UK. It has creamy-white shoots amongst the usual green shoots. Angular plumose foliage. It is listed by a few growers in the RHS Plant Finder but is difficult to source.
A variegated form of Leylandii arising from a branch sport of a 'Leighton Green' at the US National Arboretum in Washington DC around 1960. It has creamy-white shoots amongst the usual green shoots. Flat-pinnate foliage. No longer grown commercially in the UK.
Adams R P, Rushforth, K, Trimble S N (2006). Phytologia 88 (1) 1-14.
The Hillier Manual of Trees & Shrubs 2007. A David & Charles Book.
Hatch, L C (2007) Cultivars of Woody Plants. Volume 1 A-G. TCR Press, Raleigh, North Carolina
Mitchell, A F (1985) Clones of Leyland Cypress. IDS Yearbook 1985: 97-100
Ovens, H, Blight W & Mitchel A F (1964) The clones of Leyland cypress. Quarterly Journal of Forestry 58: 8-19
RHS Plant Finder.