The aim of hedge trimming is to encourage tightly packed shoots – left unpruned, they will become an unruly thicket.Pruning stimulates dense growth and reduces the plants’ natural tendency to grow as rapidly as possible, which would lead to a thin, sparse hedge.When a hedge is well-maintained and pruned regularly, it will maintain its shape, and you will be in control. Pruning a hedge is not a difficult task, and a well-maintained hedge is achievable without too much effort.he phrase ‘formal deciduous hedges’ refers to deciduous hedging that is there to look smart! Hedging plants such as Buxus, yew, and Leylandii generally fall into this category. The conifer hedges can require pruning two or three times a year to keep them under control.
When to Prune
Deciduous hedges such as hawthorn and hazel can be trimmed between June and September. But cut beech and hornbeam no later than mid-July if you want to enjoy the persistent winter leaves, as the resulting new growth needs time to get established. Tackle any major pruning as the plants go dormant and don’t prune in very dry weather.
How often to Prune
Most deciduous woody plants, including beech and hornbeam put on two flushes of growth in a year – one main flush during spring, and a second, smaller spurt during late summer. Ideally, they should be trimmed back after each flush to keep them tidy.
Tips for Flowering Hedges
Flowering hedges should be pruned at different times. Cut spring-flowering forsythia in early summer to ensure plenty of mature wood to carry the next display. Trim lavender as summer ends to stimulate flowering next year. Prune fuschia hedges in early spring, as late pruning can leave new growth vulnerable to winter cold.
Tips for formal hedges
If you’re cutting a formal hedge it’s worth putting up a line string to keep it level. Set the line of string by eye or by measuring from ground level on each cane, ensuring that the string is the same height all the way along. If there are any dips in the hedge that fall below the line, leave them uncut so that they can fill out
Tips for large-leaved hedges
To minimise damage to individual leaves, hedging plants with large leaves, such as hornbeam, are best cut with secateurs rather than shears or a hedgetrimmer. The extra time and effort is worth it, if the hedge is in a very visible position. When using a hedgetrimmer or shears you end up with a lot of cut leaves and these can turn brown and unsightly in hot weather.