The Leyland cypress, Cupressus × leylandii, often referred to simply as leylandii, is a fast-growing coniferous evergreen tree much used in horticulture, primarily for hedges and screens. Even on sites of relatively poor culture, plants have been known to grow to heights of 15 metres (49 ft) in 16 years. Their rapid, thick growth means they are sometimes used to achieve privacy, but such use can result in disputes with neighbours whose own property becomes overshadowed. The tree is a hybrid of Monterey cypress (Cupressus macrocarpa) and Nootka cypress (Cupressus nootkatensis). It is almost always sterile, and is propagated mainly by cuttings.
A large, evergreen tree, Cupressus × leylandii reaches a size between 20 and 25 m high, with its leaves giving it a compact, thick and regular habit. It grows very fast with yearly increases of 1 m. The leaves, about 1 mm long and close to the twig, are presented in flaky, slightly aromatic branches. They are dark green, somewhat paler on the underside, but can have different colors, depending on the cultivar. The crown of many forms is broadly columnar with slightly overhanging branch tips. The branches are slightly flattened and densely populated with scaly needles. The tree bark is dark red or brown and has deep grooves.
The seeds are found in cones about 2 cm in length, with eight scales and five seeds with tiny resinous vesicles. With the tree being a hybrid, its seeds are sterile. Over time, the cones shrink dry and turn gray or chocolate brown and then have a diameter of 1 cm.
Uses
They continue to be popular for cultivation in parks and gardens. Leyland cypress trees are commonly planted to quickly form fence or protection hedges. However, their rapid growth (up to 1 m per year), their thick shade and their large potential size (often more than 20 m high in garden conditions, and they can reach at least 35 m) make them problematic.
How to Grow Leyland Cypress Trees
Leyland cypress trees need a location in full sun or partial shade and a rich, well-drained soil. Avoid windy sites where the tree may be blown over.
Plant the tree so that the soil line on the tree is even with the surrounding soil in a hole about twice as wide as the root ball. Backfill the hole with the soil that you removed from it without amendments. Press down with your foot as you fill the hole to remove any air pockets that may be present.
Leyland Cypress Care
Leyland cypress trees need very little care. Water them deeply during prolonged drought, but avoid overwatering, which can lead to root rot. The tree doesn’t need regular fertilization. Watch for bagworms and, if possible, remove the bags before the larvae they contain have a chance to emerge.
Growing a Leyland Cypress Pruned Hedge
Its narrow, columnar growth pattern makes Leyland cypress ideal for use as a hedge to screen out unsightly views or protect your privacy. To form a pruned hedge, set out the trees with 3 feet (1 m.) of space between them. When they reach a height about a foot (31 cm.) beyond the desired height of the hedge, top them to about 6 inches (15 cm.) below that height. Prune the shrubs every year in midsummer to maintain the height and shape the hedge. Pruning during damp weather, however, can lead to disease.