These attractive ornamentals can be trained in winter to maintain the desired shape.
Decorative value
Acers are frost-hardy trees valued for their shape and for features such as spring and autumn colour. Most Acer species should be pruned in winter when dormant, as they will bleed badly if pruned in spring. However, snake bark maples should be pruned in late summer.
Pruning style
Young trees should be pruned so a central leader is allowed to form. Once this has been achieved, keep pruning to a minimum, so trees maintain their graceful shapes. Reduce height and width where necessary by following long branches back to a side branch and pruning out at that point. For prostrate trees this is not necessary and they should be allowed to spread naturally.
Acer negundo ‘Flamingo’, a popular variegated acer, can be pollarded each year to encourage vigorous growth, large leaves and the best leaf colour. Pollarding should be carried out in late winter.
Maintenance
Maples are prone to stem die-back. Where this happens, prune the dead stems back to healthy wood. If leaves become scorched it is not necessary to prune back unless the stems are damaged, because a second set of leaves is likely to be produced.
Sarah Durrant