The best time to trim a hedge will depend on the type of hedges you have. Most hedges can be trimmed several times during the summer when they start to lose their nice shape. However, if you have a flowering hedge, you should avoid trimming until it stops flowering Otherwise, you may do more harm than good and stunt the growth of your hedges. Deciduous hedges are best trimmed in the early spring before any real growth begins. You can also trim these ones just before the winter.\r