when is the best time to hard prune my copper beech hedge?

Answer 1

The RHS recommends deciduous stocky shrubs, naturally bushy at the base, e.g. beech, hornbeam, hazel and flowering shrubs such as Forsythia and Ribes sanguineum be treated as a group.

"On planting (October-March) cut back leading shoots and sideshoots by one-third, cutting to a well placed bud. Repeat this in the second winter to prevent straggly growth and thicken up the hedge base."
"Annually in June (or after flowering) and again in August, clip to a tapered shape."

Answer 2

THE END OF FEBUARY OR MARCH.

Answer 3

fall.