x Cupressocyparis leylandii
And so to the biggest garden thug of all in the garden! We seem to spend half the time here cutting down greedy leylandii hedges because we hate and detest them and half the time planting them again as new windbreaks because they grow so quickly and efficiently.
x Cupressocyparis leylandii is a hybrid genus created by a cross between Chamaecyparis and Cupressus. It is the fastest growing conifer ever created and was first raised in Northern Ireland in 1962. It can easily grow 2-3ft a year and achieve 45ft in only about 15 years. It grows as fast as a eucalyptus!
This is why, as a hedging plant, it causes so much dispute and hassle between neighbours when rows of leylandii obscure light to properties and take all the moisture out of the ground causing subsidence to properties as the roots grow with age.
It is perfectly possible to clip and train leylandii into a formal hedge at 6-10ft in height but this requires a great deal of work and trimming more than once a year. As a long term project the leylandii will generally beat you. If you cut a leylandii back beyond the new growth to old wood it will not reshoot and you will be left with a ‘dead’ area in part of the tree.
In the nursery a ‘bright spark’ trimmed the row of x C. leylandii ‘Castlewellan’ with its golden young foliage far too hard in just this way and one side of what was once an efficient windbreak for the outside standing beds is now lifeless on one side. It will not reshoot and will have to come out completely to start again with a new evergreen windbreak.
In a woodland setting, more mature leylandii hedges do suffer from trees splitting off at the base of the tree in strong winds. If we are establishing quick windbreaks in people’s gardens, perhaps in the teeth of coastal wind, it is an idea to grow leylandii as the outer line or wind protection which gives the next layer of defence time to get going. This works well with laurel, bay and ilex oak which are slower growing. In 10 to 15 years the leylandii can be dug out with a mini digger and the whole tree removed; stumps and all. They burn satisfyingly well.
So it is a love/hate plant which has great value in the right context and very little – quite the reverse – in so many others!
