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.