A well-maintained hedge provides a good, smart boundary to a garden, but if left unchecked, a hedge can soon lose its shape and end up casting unwanted shade. With a good pruning schedule you can keep hedges under control without too much effort
When to trim
Most evergreen formal hedges like to be trimmed two or three times a year, while they are actively growing. Pruning informal hedges depends on when they flower. Lavender, fuchsia, roses and other plants that flower on the current year's wood are best pruned in early to mid-spring, while those that flower on old wood, such as forsythia, deutzia and berberis, should be pruned when the blooms fade.
Hand shears are fine for short runs of hedge, but if it is long, invest in an electric, battery or petrol-powered hedge trimmer. It will make light work of the job and won't leave you with tired arms. If you use an electric trimmer, make sure it is plugged into a safety socket fitted with a residual current device or circuit breaker, so that the engine will cut out if there's an accident. When trimming keep the cable away from the blade, ideally draped over one shoulder rather than trailing on the ground.
How to clip a formal hedge
Start by pruning the top flat. If the hedge is not too long, you should be able to cut by eye, stepping back occasionally to check your progress. If you don't trust your eye, hammer two stakes into the ground and stretch a length of string between them to use as a cutting guide. Next, cut the sides, making the top narrower than the base. Brush off trimmings from the top of hedge and from the base of the hedge to prevent the spread of fungal diseases.
Although flowering, informal hedges are allowed to grow naturally so that their shape isn't spoilt, that doesn't mean they never have to be pruned. If neglected they could soon grow too tall or spread out of their allotted space. To keep them in good shape, occasionally remove old stems with secateurs or cut branches to keep within bounds.
How to prune dwarf hedges
Low growing hedges used for parterres, knot gardens or as borders around vegetable beds can be kept neat by trimming twice a year. Cut box, rosemary, lonicera, lavender and germander in spring and then in mid-summer. Use string stretched between two stakes to ensure the top is flat and then cut the sides vertically.