Leylandii: planting menace in the mind

Cypress Leylandii (centre), Mill Lane, Bridge. Given space to grow, Leylandii is not unattractive in itself. Image © copyright BridgeNature.org 2016

Leylandii, that notorious, rapid-growing, evergreen, furry monster which has blighted suburban gardens and caused domestic disputes across the country for decades: we all recognise it and despise it, don’t we? Well things are not quite what they seem…

Members of the Cypress tree family(1) are generally recognised by their evergreen, fern-like branches. Cypress Leylandii is a man-made hybrid within that family. It was created in Britain in about 1888 by arboriculturists who were sharing conifer seeds imported from America. It is not clear who actually produced the first tree of this particular hybrid but a certain Mr Leyland got the credit, or should we say blame? Leylandii is fast growing and can grow to 50ft in 15 years or so, and it will grow to 150 feet if left unpruned. It was created by crossing two North American trees, the Nootka Cypress from Alaska, which provides great hardiness, and the Monterey Cypress from California, which gives it rapid growth. In their natural setting, both of these trees are really quite beautiful and they would never have cross-pollinated naturally.

Leylandii became popular in modern British gardens when it was discovered that, planted in a close row, they quickly provide an effective tall screen to give privacy. However, pruned closely such hedging can appear overly severe, yet if not controlled at all, the trees rapidly outgrow their setting and become a nuisance.

Bridge Tennis Club. Strictly controlled conifer hedging can look overly severe, and hard pruning leaves ugly bare patches which may never recover. Image © copyright BridgeNature.org 2016

Yet, surprisingly, people who complain about Leylandii in their neighbours’ gardens may not actually be seeing Leylandii at all, they may be looking at another similar tree in the Cypress family, the Lawson Cypress. Sometimes called a False Cypress, this tree is in fact a cedar, known in America as the Port Orford Cedar because it comes from that region of Oregon. It was introduced to Britain in the 1850s by the Lawson nursery in Edinburgh. It is often planted for hedging for similar reasons to Leylandii. Its flowers can make it a more attractive tree, but if left untended, it causes the same problems.

Male (red) and female (brown) flowers on this Lawson Cypress on Patrixbourne Road can make it an attractive tree in spring. Image © copyright BridgeNature.org 2016

However, this is not yet the full story: another group of similar looking trees in the Cypress family, also commonly used for tall hedging in Britain, are the Thujas. These are again cedars, notably the Western Red Cedar and the White Cedar from the Pacific coast of North America. While all these different possibilities make identification complex enough, the situation is further complicated by the fact that over the years all these trees have been further crossed and selectively bred to create size, growth habit and colour variations which range into the hundreds.

The distinctive cone of a Thuja growing in Bekesbourne churchyard. Image © Copyright BridgeNature.org 2017.

In all the furore over Leylandii’s role in irresponsible hedge planting, conifers in general have gained a bad reputation which they do not really deserve. The original trees that created some of the most notorious hybrids were all selected because they were and are hansom trees in their own right. In the correct setting they make wonderful specimen trees and their wood is highly valued by craftsmen across the globe: the timber of Port Orford Cedar is used in America and Japan for making arrows and musical instruments; Thuja wood is very decorative, so it is often made into ornamental bowls and boxes; Nootka Cypress is considered one of the most useful timbers in the world, it is very resistant to rot and is often specified for the construction of wood cabins, decking and traditional small boats.

What a shame it is that, simply because of unsuitable placement in modern suburban British gardens, many conifers have been tarred by one common villainous appellation ‘Leylandii’, a name which arouses such contempt amongst the British public.

(1) In arboricultural circles there has been and remains a great deal of debate about which trees actually belong in the Cypress family and which should be placed into other groups. For the sake of simplicity here we have tried to cite commonly accepted classifications.

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