ever heard the song "down to stems and seeds again" by commander cody? you can smoke all of the plant (and desperate people have). you do not have to just smoke the bud. a good female will ahve different quality smoke from the lower leaves to the trim to the bud. i suppose just about everyone has cut a leaf, micorwaved it and tested the buzz (and towards the latter stages of flowering -- it is a pretty good buzz).
regarding the original question of planting a leaf -- whatever that person's smoking, i want some!