This can relate to how Montag feels about not knowing about why they burn books and how it started; he feels very bothered and wants answers. It can also be what Montag sees when he has to burn books with a woman inside the house.
Flaming Roses (note to self: maybe a burning rose can be a symbol of passion and love in this world. Would make for good back story and a beautiful plot device. Would make the symbolism of stuff more dramatic, too.