Add extra colour through the year with a flowering hedge. There's lots of choice - why not plant a mixed hedge? Alternate a plant that flowers in the spring, with one that flowers in summer, and you've got two seasons of colour in the space of one!
If you want plenty of flowers, don't clip too often! Take care what time of year you clip, so you don't cut off branches that will flower later. Pruning after flowering usually ensures a good season next year.