Are they sprouting, or is it like "We really want to say 'Springtime in Japan'" stuff where sakura petals keep falling all day everyday in Spring even when characters aren't anywhere near a tree. The fact that Teetoku's hat and shoulders are covered in petals seems to support the latter, unless she was deliberately tossing some on her head.
If it's falling, the princess-carriers would probably be deluged with flower petals as they walked (hope you don't have allergies!) and probably need to watch their step, since they would probably be rather slick.