Is marijuana just like any other plant?

No. You don't actually smoke the 'plant'. There are female and male marijuana plants, males simply grow leaves and can pollinate the female, and the female grows the buds, which you (or people) smoke. When the female plant grows the buds (which contain the THC that creates the desired high), they can be picked and smoked immediately. But you don't smoke the actual leaf of a marijuana plant. Hope this helps.