Leyland cypress trees (x Cupressocyparis leylandii) are an intergeneric hybrid between Cupressus macrocarpa and Chamaecyparis nootkatensis. It was named after C.J. Leyland, who grew some of the first plants in England in the early 1900s. It has a large potential growing range in the United States, along most of the East Coast, West Coast and Southern regions of the country.
Leyland cypresses are evergreen, coniferous trees with a dense pyramidal form. They grow rapidly, reaching a height of 50 to 100 feet or more, with 15- to 25-foot spread. Their scale-like foliage forms on flattened branchlets and is feathery in appearance. The foliage is soft green when young, changing to dark blue-green as it matures.
Leyland cypresses make good specimen or accent trees in large landscapes, and are useful windbreaks or screens. In the South, they are often used as Christmas trees, though their branches droop under heavy decorations. Leyland cypresses are also recommended for planting along highway median strips and around parking lots.
Grow Leyland cypress trees in full sun and well-drained soil for the best performance, but it will tolerate a wide range of conditions. Leyland cypresses are very tolerant of severe pruning, although it is not recommended. Propagate by rooting cuttings from side growth.
'Green Spire' has a narrow shape and is very dense. It produces bright green foliage. 'Castlewellan' has gold-tipped leaves and is a compact Leyland cypress. 'Haggerston Gray' has upturned, loose branches and is a sage-green. 'Silver Dust' has white variegated with blue-green foliage. 'Robinson's Gold' is densely branched with bronze-yellow foliage in spring and turns gold-yellow in summer.
Leyland cypresses are not recommended for California because of the severity of canker disease in the region. Bagworm is a serious pest when present, quickly defoliating a tree. Beneficial insects feed on bagworms, usually keeping them under control. If their egg-bags are found in winter and spring, remove and destroy or place in a deep container where beneficial parasites will feed on them. Bacterial insecticide (Bt) is most effective on young larvae. Pay close attention to pesticide label precautions and directions before use.