How to Prune Californian lilac 'Dark Star'?
For free-standing plants: Usually little pruning is needed. Lightly shape if necessary, removing dead, damaged or diseased shoots. Prune after flowering. For wall-trained specimens: On established wall-trained shrubs, shorten sideshoots to two to four buds from the framework; remove shoots growing towards the wall. Prune annually after flowering on last-year growth, or in late winter or early spring on current-year growth.