I can't see it just being harry having fallen asleep... I think that there has to be more of a reason why he's lying there particuarly, or that someone else was the cause of him being specifically int he flowers.
Even though he's got Sirus to bully the Dursleys with, he always tries to stay out of trouble when he's at Privet Drive... he's never openly remeled against them, just hinted taht sirus would be unhappy if he didnt' get to leave... like that... For him to have purpously have gone to sleep on a bed of flowers, he would ahve known that he would be in trouble for it...
Maybehe needed to be surrounded by flowers for something magical to happen???
