During summer you can fine-trim as much as you want, periodically snipping outgrowth during the growing cycle will encourage growth and make it branch upwards. If needed, do two major trims – one in the middle of summer and the other towards the end.
Be careful when choosing what tools you use. Cheap tools often loose their edge fast and a dull blade can do more damage than good by squeezing while cutting, thus getting in the way of the healthy re-growth. To achieve the best result use hand pruners for the majority of the fine work, hedge shears with serrated blades for heavier branches and lopping shears for the thickest ones.
• Hand pruners or secateurs – to be used for finer work
• Hedge clippers – preferably with serrated blade for heavier branches
• Pruning loppers – for the thickest branches
• Electrical hedge trimmers – double-sided for shaping or single-sided for the straight portions of the hedge.
To trim your hedges into an even, beautiful shape, you might want to use strings (or a measure laser) as guidelines. First you get rid of the ”main offenders”, large branches sticking out, then get down to the fine pruning. Hedge sides should be trimmed wider at the base to provide maximum light and sun for the exposed leaves. The hedge should resemble a vase turned upside-down.
So, what has to go? If you’re trimming it down for re-growth you can focus on long branches in the middle whereas if you’re just ”fine-tuning” you can concentrate on shape, evenness and thinning out. Start from the top and work your way downward. Also remember to fertilize the hedge to give it energy and to stimulate further growth.
With these few tips – and a bit of old-fashioned, hands-down work – you should be able to achieve a good-looking, healthy hedge with a minimum of trouble!