As with all pruning ideas, you will find that opinions abound. They are everywhere, and everybody has two or three. Plants don’t have opinions; they just BE. No matter what we do to them, if they can carry on, they will. The topped tree grows a new leader. The hedged shrubs grow new shoots and flowers, perhaps for the first time in years, and so on. In other words, each plant is hardwired to be that plant and the best thing you can do is to realize it and work with it. If not, your garden will not feel free and happy; it will have a constricted feel.
Where have all the flowers gone?
We all have our plans and styles, and sometimes a feature plant done with topiary is pleasing to see. But if you want flowers on shrubs, your pruning is going to have to align with the natural growth form of the shrub. Almost all shrubs flower on current or last year’s growth. When this is removed by shearing, so are the flowers. This is why foreknowledge of shrub size and form is paramount—it will allow you to plant the right plant in the right place, care for it, and watch it smile.
Like trees, shrubs feel better when the pruning is kept to a minimum. Sure, clean out the shoots and diseased and dead wood; that’s just common sense. After that, you have moved into the realm of craft, art perhaps, so be careful. I know you can do this, just look and think a lot first.