Accepted name: Cupressus ×leylandii
A species with the parents Chamaecyparis nootkatensis x Cupressus macrocarpa with most cultivars forming vigorous columnar to narrowly conical trees growing extremely rapidly to 20 m or more in 20 years with the branchlets generally flattened. Leaves mostly coarse, slightly spreading and ridged on the back. Cones when present, 1.5-2 cm wide with 8 scales. Seeds usually 5 per scale, warty.
First raised in 1888 at Leighton Hall, the property of a Mr Naylor at Welshpool, Wales, UK, the seed parent being Chamaecyparis nootkatensis which was growing near a Cupressus macrocarpa. Seedlings were transferred to Haggerston Castle in Northumberland by C.J. Leyland. In 1911 the cross was produced a second time when the seed parent was a Monterey Cypress at Leighton Hall. Formal description did not occur until 1925 when Dallimore and Jackson described two plants from Haggerston and one from Leighton. First established as Cupressus x leylandii; the recognition of Chamaecyparis as a separate genus from Cupressus involved the transfer to XCupressocyparis in 1938. The cross has since been repeated and there have been many numbered but unnamed clones produced.
The common name commemorates C. J. Leyland, owner of Haggerston Hall, where the first seedlings were sent.
The Leyland Cypress is an extremely vigorous tree and probably the fastest-growing conifer at about 1 m a year. It first came into general commerce in about the 1930s in the United Kingdom but considerably later in Australia. It will grow in a wide range of soils and can be clipped; it is widely used as a shelter or windbreak but caution is needed for use in the home garden because of its rapid growth to a large size. It will not grow well in Canberra.
NSW: Sydney (Royal Bot. Gds); Mt Tomah (Bot. Gds); VIC: Melbourne (Royal Bot. Gds, cutting from the original cross were growing inside 'F' Gate in 1993); ACT: Yarralumla (Nsy).
Recognition: Distinctive narrow-conical habit; coarse foliage with ridged leaves slightly spreading, generally most similar to C. nootkatensis but cones larger, c. 1.5-2 cm wide with 8 scales.
Created by: Roger Spencer
Updated by: Roger Spencer, May 2018
('Castlewellan Gold', a name under which this cultivar is best known, is a later name and therefore without priority). Sprays dark blue-green with gold tips. This cultivar has an attractive upright form but is a rapid grower that should not be planted in small gardens. Originating on the property Castlewellan Forest Park in County Down, Ireland from seed collected by Mr J. McKeown from a Cupressus macrocarpa 'Lutea' which was growing next to a Chamaecyparis nootkatensis 'Lutea'. Introduced probably in the late 1960's and widely propagated after 1970, available in the 1980's in the UK and Australia and soon becoming the most popular of the Leyland Cypresses.
('Peter Nitschke') a compact, dense, ovoid, slower-growing form of 'Castlewellan' with greener more juvenile foliage at first. A seedling selection of 'Castlewellan' by Peter Nitschke and J. Koelewyn. Scions from the original selection were veneer grafted onto 'Castlewellan' rootstock and the clone then propagated asexually. Literature: J. Koelewyn. Plant Variety Rights Journal 5(2):10. Application 91/094.
Branchlets semi-erect, yellow with green tips in winter changing to deeper yellow with dark yellow narrow margins in summer. The incorrect name 'Golden Rider' is sometimes used. A branch sport of 'Leighton Green' in the Netherlands and said to be sold there under the name 'Gold Rider' since 1986, although this may be a mistake for the name 'Gold River' recorded by Welch (1991). Introduced to Australia in 1990. Literature: l. Koelewyn. Plant Variety Rights Journal 3(1):21 Application 91/012.
Narrowly columnar densely branched tree with bright green foliage. Foliage cypress-like although with flattened sprays. Originated C.J. Leyland, Leighton Hall, Welshpool, UK in 1888.
Narrowly columnar but becoming broader with age. Foliage coarse, in flat pale yellowish green sprays with the leaves in two ranks, most closely resembling the Nootka Cypress; it often develops cones. J.M. Naylor, Leighton Hall, Wales, 1911, introduced UK c. 1935.
Openly branching with foliage dark grey to grey-blue, most similar to C. macrocarpa of all the clones. Rarely develops cones. J.M. Naylor, Leighton Hall, Wales, 1911.
Foliage white variegated; similar to 'Star Wars'. Origin Netherlands c. 1990.
A sport of 'Leighton Green' with irregular patches of creamy foliage, arising in 1960. Raised by S.G. Marsh at the National Arboretum, Washington DC, USA.
('Stapehill 21') and 'Stapehill' ('Stapehill 20') Columnar trees, the former drought sensitive, the latter superior with rich green luxuriant foliage. Presumed Leyland Cypresses developed at the nursery of M. Barthelemy at Stapehill, Ferndown, Dorset, UK.
Very similar to 'Seribo' with white variegations evenly distributed through the foliage. Branch sport selected at Coolwyn Conifers, Monbulk, Victoria, Australia and introduced c. 1992.