How long does it take to grow mint leaves?

In a garden it is best to harvest/pick them (1. time) when they are blooming (because you dont want them to set seeds, because those seeds will become plants with less taste, and mint spread enormusly fast) It is important when you pick them that you doesnt take them from the root but make sure there is still fresh leaves in the remaining piece of plant. It will then grow from those leaves very fast so you can pick them again later in the year. But mint is so easy to grow that it doesnt matter if you do something wrong - I just pick when i need them and just remove the flowers when they are just about to make seeds