They start to flower once the days get shorter so if you plant in spring it will get quite big before the days get shorter and the start to flower if you plan after the days start getting shorter the will not get as big and will flower sooner. If plant in a pot in spring you can move them to a spot which gives then less daylight to induce flowering
There are some strains that have been breed to flower more quickly.
Interesting, I know some one that get medicinal cannabis and surprised to hear they send it to him via Australia post
