Thinning and Heading cover clipping, cutting, pruning and trimming. But before you set to on your hedge, consider this simple process from the hedge’s point of view…
Thinning and Heading. both cause what’s known as abiotic damage and although you are being cruel to be kind, the nature and severity of this so-called ‘damage’ does determine how the hedge will respond. And this response dictates the optimum time to carry out either of the tasks:
Thinning is the more severe of the two procedures and refers to the cutting away of branches or shoots right back to the node from which each one is growing. The aim is to control growth and/or to increase the amount of light that can reach the lower branches.
The recommended time to thin is late winter. First, because the bacteria and viruses that would otherwise attack through the cut wood are less in evidence and many will be dormant. Second because the plant itself will still be dormant and therefore less likely to produce unwanted suckers in response. Third because the plant will be best equipped to self-heal the resulting wounds. And finally because it minimises the time before the plant comes out of its dormant period and starts growing again.
However, as mentioned before, in nature there is no such thing as a hedge – a hedge is simply a row of trees or shrubs grown and managed in a particular way to create what we then recognise as a hedge. A hedge, therefore, rarely has to be ‘thinned’ but as many hedging plants are grown as stand-alone specimens or in a looser form somewhere between individual plants and a fully formal hedge, it is worth understanding the biology of this process.
We’ll consider Heading in the next post.