Will pruning help my lilac flower?
One of the reasons a lilac may fail to flower is lack of sunshine. They don’t like to be grown in shade. Pruning won’t really help and if you prune at the wrong time you may actually trim off the flowering shoots and buds. As your lilac gets taller and reaches more light you should get more flowers. Apply sulphate of potash to the soil in August or September to help the stems ripen and promote flowering.