The best solution in situations like these is the use of either an aerial hedge , or to use a latticed fence extension and grow a vine on it. In many cases, privacy is not needed in the garden during the winter. If this is the case, you have a much larger selection of plants, including deciduous shrubs and trees that give you a showy season spring, summer, or fall. The larger plants typically grow the fastest, but they also require more yearly pruning. Photinea and Privet, when growing well, can require 3 or 4 prunings a year to maintain their shape.
Many plants also change their shape, or lose their blooms when regulary pruned.
If you want an informal look it is often best to choose plants that do not need to be pruned often. These are plants that have one or several exposed trunks to a height of 5 or 6', and then are hedged. Additionally, mixed screens can go longer between prunings because it is not necessary to maintain a sheared look.