cannabis is an annual plant, but is possilble to re-veg under artificial lights. and in some tropical climates is possible to re-veg outdoors. i once left two female plant full of buds mature and the plants re-veg leaves and branches from inside the buds and i let them grow the end result is very mature buds mixed with fresh buds but during this process they lost some potency. i think i have one pic of that. here you can see, is the first 2 plants.
they re-veg outdoor.
click to see my new grow 07/08