In the Pacific Northwest pruning for most plants can be done year round. We avoid pruning certain shrubs because we do not want to remove their flower buds. Pruning plants which are marginally hardy (some broad leaf evergreens) in the fall may make them more susceptible to winter damage. Spring pruning may cause excessive sap flow with certain plants. Although this causes concern, there is no damage to the plants.
It is easier to see what to prune on deciduous plants by pruning when they are dormant (without leaves). However, pruning when leaves are present is not harmful to deciduous plants.
Coniferous (Needle leaf) Evergreen Trees and Shrubs can be pruned any time of year without detrimental consequences.
Broadleaf Evergreen Shrubs and Trees can be pruned at any time of year. However, fall pruning (September, October) should be avoided for marginally hardy plants such as Escallonia, Choysia (Mexican Orange) and Viburnum Spring Bouquet. Pruning stimulates new growth just before cold temperatures can cause damage.
Deciduous Trees can be safely pruned at any time of year, although it is easier and faster to prune when leaves are not present. Upright growing water sprouts and suckers should be removed by snapping them off when less than 12 inches long (generally June-July).
Fruit Trees are best pruned while dormant (November-March). They should be pruned every year for best fruit production. Upright growing water sprouts and suckers should be removed by snapping them off when less than 12 inches long (generally June-July). If they are allowed to remain until the next dormant season they will be quickly replaced by new sprouts.
Spring Flowering Shrubs form new flower buds during the late summer and fall. If pruned after buds are set, but before spring bloom, some of these buds will be removed resulting in fewer flowers to be enjoyed.
Summer Flowering Shrubs develop their flower buds in the spring shortly before bloom. They can be pruned after bloom and during the fall and winter months. Pruning in the spring will usually reduce flowering.