Beech, known botanically as Fagus sylvatica, is a deciduous ornamental shrub that can be used to establish attractive hedging in areas protected from wind and severe weather. According to the Royal Horticultural Society, beech hedges should always be pruned in the late summer, preferably in August, to preserve the second set of leaves on the shrub through the winter. Young hedging should be trained and shaped by consistent annual pruning for the first few years after planting, if not already in perfect form.
Prune young beech hedges in their first year after installation if the branch structure is wildly uneven or asymmetrical and will show when the plant is entirely leafed out. If the young plants are well proportioned and roughly uniform along the run of the hedge, pruning is not necessary in the first year. Your goal is a branch structure that is full and fairly uniform to make a lush, thick hedge without holes when fully leafed out.
Correct poor branching structure in the first and second years by heading back the longest branches and shoots to the desired uniform height or spread. Follow up by removing just the terminal tips of the other shorter branches to encourage bushiness and branching at the tips. Place all cuts on the bias and just 1/4 inch above a leaf node or bud.
Establish the basic perimeter lines of the hedge form in the third year after planting and each year thereafter. Taper the hedge slightly as your go up to ensure the lower branches receive sunlight and will not become denuded. A gently flared base of 3 1/4 feet tapering in as you rise to the top of the hedge is recommended by the Royal Horticultural Society. Hold the pruning shears roughly parallel with the hedge surface to make flat plane cuts that blend easily into one another for a smooth, level hedge surface.