Lots of folk are stuck with a overlarge Leylandii hedge. Apart from its vertical growth there’s a problem with its lateral growth as it encroaches more and more upon the garden. The problem with trimming such a hedge is that unlike, say yew, Leylandii will not not regrow if you cut it back beyond the last leaf cluster. Therefore, even if it is trimmed on a regular basis, it will tend to get thicker and thicker over the years.

If your side of the hedge is on the sunny side then there is a desperate measure you can take to save your garden from disappearing. You can cut the Leylandii back to its trunk on its South side, safe in the knowledge that the branches on the other side will turn and send leaves back towards the light.

I worked in a garden with three Leylandii hedges. I cut back one hedge five years ago and the leaves have grown back substantially. see Fig 1.

The owner is happy with the thickness of the hedge as it is now and keeps it trimmed back to the level of the trunks. You could have it to any thickness as this hedge can now be trimmed with impunity because all the branches are coming from the other side and have leaves further back.

So pleased is he that I have recently done the same to a second hedge and here is the result about a year on- fig 2. OK, I know it won’t look very pretty for a few years until the leaves grow back towards the light. With my hedgelaying skills I have helped things along a bit by not actually cutting through all the forward growing branches but pleaching some of them so that they grow sideways fig 3. Also you can help things by pulling through some of the branches growing the other way.

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I very much doubt if this would work if the section of hedge you want to cut gets less light than the opposite side.

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The third hedge wasn’t suitable for this treatment. It was decided to replace the Leylandii with other evergreens, mostly yew. The owner preferred to keep at least some of the Leylandii for a few years as they provided a useful windbreak. Now, conventional wisdom is that you can’t grow a new hedge under Leylandi because their massive growth rate means that the nutrients are taken rapidly out of the soil. But after discussions we gave it a go. The Hedge was thinned out by taking out every other leylandii and all the lower branches of the remaining leylandii were taken off to allow light and rain to the new hedge. The new hedge was then planted in the place of the removed trees. The hedge was nurtured rather more that most with regular mulching and watering via a leaky hose system.

Somewhat to our surprise, it has worked: fig 4. The new hedge may not have grown quite as fast as it might but it has survived with the loss of only one plant. We’ll be getting the remaining Leylandi down soon.