The Leyland cypress is a well-known evergreen in England, the United States and Australia. Large landscape projects and open areas needing wind protection often use this tree. Grass and weeds have trouble growing underneath a Leyland cypress because its roots release a natural herbicide to keep other plant life from invading. This is because the root system is shallow and must fight smaller plants for water and nutrients.
Leyland cypress is scientifically labeled x Cupressocyparis leylandii, according to the University of Florida. As a younger tree, the Leyland cypress grows 3 to 4 feet per year. Leyland cypress is a false-cypress, meaning that it does not do well in standing water, as true cypress does. It is in the Cupressaceae family of trees. Although this tree grows in USDA zones 6 through 10A in the United States, it is not native to North America. The Leyland cypress is an evergreen tree, never changing colors during cooler months. The tree has a pyramid outline when untrimmed.
The main feature of this tree is the height and spread of the branches. At full growth, the Leyland cypress can grow to 50 feet high and 25 feet wide. This evergreen has a bark resembling skin that can be torn easily when cut. The symmetrical canopy has a smooth outline because of its fine, scalelike leaves. The leaves are less than 2 inches long and have a color range from blue, through blue-green to green. There are no flowers, and the fruits of the tree are brown, hard and small, being under 1/2-inch round. The limbs are resistant to breaking, making this tree adaptable to wind-prone areas. The Leyland cypress can also handle dry areas and grows in a range of soils, from pure sand to pure Georgia red clay, according to the Aucker Nursery. The best pH level for the tree is between 5.5 to 6/5, although it can grow in a range as high as 8.0 pH. The Leyland cypress also withstands deep cold; younger trees can tolerate temperatures as low as 8 degrees F, while older trees can withstand 0-degree temperatures.
The Aucker Nursery states that the Leyland cypress is a hybrid tree discovered in 1888 by C.J. Leyland, from whom the tree gets its name. The trees were found as seedlings at Leighton Hall in southern Wales, which is part of the British Isles. The parents of this hybrid form are the Monterey cypress and Alaskan cedar. The tree species was developed further through the 1900s by Leyland and J.M. Naylor. Rooted cuttings came to California in 1941. Clemson University was the first to use Leyland cypress as Christmas trees in 1965.
Leyland cypress trees have many uses, from ornamental landscaping to wind breaks and wood products. England uses this tree as ornamental landscaping and wind breaks. People of Australia use the tree for wood products. In the United States, it is sought after for landscaping and Christmas tree use.
The Leyland cypress is not very pest-resistant. The most common pests affecting this species are the bagworm, scale and spider mites. Bagworms are the most problematic because they can defoliate a tree within two weeks, according to the University of Florida. These pests can be hand-picked from small trees, states Aucker Nursery, but must be handled with chemical sprays on larger, mature trees. Scale is an insect that feeds on sap. Needles of the tree turn yellow, and the entire tree has an appearance of crusty flakes covering the needles and branches. Chemical sprays are also used in springtime to get rid of scale. Spider mites are the most difficult to control because of their size. These sap-feeding insects are visible only under a magnifying glass. These insects cause the Leyland cypress needles to turn yellow, then brown.
Leyland cypress trees also have four common diseases that affect them: Seirdium canker, Botryosphaeria canker, Cercosporidium Blight and Phytophthora root rot. The Seirdium canker kills branches and entire trees, and the Botryosphaeria canker is less severe and kills branches. No chemical controls are known for these diseases. Cankers are usually found following drought, according to the University of Florida. Cercosporidium Blight is an aggressive fungus that moves quickly because it is an airborne fungus. Noticeable yellowing and dropping of needles will occur starting on the inside lower branches, then moving out and up. Trees that have seen excessive sheering, sun or drought are prone to blight. Phytophthora occurs on trees with poor drainage; it causes the roots to rot and die.