Late summer is a good time to sharpen those secateurs and prune certain shrubs, trees and hedges. Summer pruning of trained fruit trees helps to maintain their shape and form – a conversation for another time – but a number of evergreen hedges can be trimmed now to provide crisp features. Cutting hedges towards the end of August ensures that the majority of growth has already occurred that season – think of a line graph where vigorous growth tends to peak around May, June and July and starts to tail off in August and towards September. The benefit of cutting some hedges now is that there’s enough growing time left in the summer to be able to cover our pruning cuts and for the hedge to soften slightly, but not enough growth to compromise the shape we’ve created.
Nesting birds need help more than ever. By the end of August, nesting season should be over, but before you carry out any pruning, check the hedge first, to ensure that there are no viable nests – if there are, then put your hedge trimmers away for a week or two until the chicks have fledged.
Beech, yew, elaeagnus, holly, hornbeam, box and mixed native hedging can all be trimmed at this time of year – not forgetting privet. There are many gardeners with a passion for topiary and a crisp, privet hedge that will need pruning every few weeks to maintain the sharpest of shapes, but for me, cutting hedges once a year is more than enough.
Start by trimming the sides of the hedge, and then finish with the top. You are looking to remove all the young growth, which is less than a year old, cutting back to the point where this year’s growth begins. You need to prune reasonably hard, to avoid your hedges becoming taller and wider year on year – otherwise, before you know it you will have a big rejuvenation job on your hands in the future. Use a string line to ensure straight lines. There may be areas of the hedge that you have to trim a little lighter to maintain a uniform line.
Clear away your trimmings, which compost down and add a welcome amount of woody fibre to compost heaps. If in the past your trimmings haven’t broken down, run them through a chipper before adding to your heap. Lacklustre hedges can be improved by the application of Growmore and 2in layer of mulch in the spring, when the hedge will benefit from it the most.
Read more: Can I still plant at this time of year?