x Cupressocyparis leylandii
The name Leyland cypress is used to describe a group of trees where all the members are sterile hybrids. There are no naturally occurring Leyland cypress. They must be propagated by rooted cuttings.
This tree is a hybrid of Monterey cypress (Cupressus macrocarpa) and Alaskan cedar (Chamaecyparis nootkatensis). In 1888, 6 seedlings were discovered by C.J. Leyland at Leighton Hall in the South of Wales. The two parent trees were growing on the Estate and cross bred purely by accident. Inter generic crossbreeding is a rare occurrence in plants and particularly in conifers.
The foliage of the Leyland cypress varies somewhat from one cultivar to the next. But in general it tends to be arranged in irregularly flat planes with a dark green to gray color. The shoots branch repeatedly and have a contrasting mahogany color except at the tips. The trees have little aroma.
The bark of the Leyland cypress is has a skin-like texture and is quite delicate. In its mature form, heights of 138' are expected, and the tree is capable of withstanding temperatures of about 0 F.
There are many cultivars of Leyland cypress, but the 8 most common ones are Haggerstown Grey (the original), Leighton Green, Gold Cup, Castlewellan, Green Spire, Naylor's Blue, Silverdust, and Robinson's Gold.
The Leighton Green cultivar has been most commonly used as Christmas trees. The foliage of this tree is a dark forest green. It is heavy and stout with a somewhat coarser appearance when compared to the other Leyland cultivars.
Castlewellan has very delicate lacy foliage. In winter, the exterior of the tree turns gold while the interior remains green. Castlewellans are noted for their strong tendency to conical growth.
Silver Dust is identified by the white variegated splotches on the foliage. Their leaf structure is otherwise very similar to that of Leighton Green.
Since Leyland cypress is not a naturally occurring tree, it has no natural range. But, it has been successfully grown in England, Australia, New Zealand, California, Louisiana, Mississippi, Alabama, Georgia, Florida, and the Carolinas.
This is a fast-growing evergreen when young and will quickly outgrow its space in small landscapes. It is an excellent choice for quick screens, hedges and groupings, especially on large properties.
This tree tolerates severe trimming, and can be restrained at an early age with pruning. Although Leyland cypress can be sheared into a tall screen on small lots, it is most effective when allowed to develop into its natural shape. Regular trimming is necessary to retain a formal hedge, screen or windbreak.
When considering this tree for use in a design, be mindful of its projected height. It usually grows larger than most people desire. It is a good background plant, and contrasts well with broadleaf evergreens.
This tree prefers sun to part shade and well-drained fertile soil. It is very adaptable, however, and tolerates acidic or alkaline soils and poor drainage on occasion. It withstands salt spray and is suited for coastal landscapes. Prune only during dry periods to help prevent disease.
Leylands are propagated by rooted cutting only.
Leylands can grow 60' — 70' tall and 12' — 20' wide. Heights of 70' — 100' are not uncommon. It grows rapidly when young (3' — 4' per year).
In England, the Leyland cypress is used as an ornamental and as a wind break. In New Zealand and Australia it is used for wood products. In the United States, it has become a valued landscape plant and one of the most sought after Christmas trees in the southeastern states.