This idea is really intriguing. Have you thought about how might play? Is it more of a point-and-click sandbox game, or is it more action-based, with movements and a few choice actions mapped to buttons but few menus?
It would actually be interesting to have different lifeforms control differently, to reflect just how different the flower's perspective is versus a human's. Of course, they would have to be similar enough to not confuse players, or cause them to hate one level because its gameplay is "less fun" than the others.