The symbolism of flowers (from Midnight in The Garden of Good and Evil)

A brief conversation about the symbolism of flowers, from the movie, Midnight in The Garden of Good and Evil:

MANDY: You want to send some flowers?

JOHN: I think so. I don’t know, though. It’s kind of complicated.

MANDY: For whom? What’s she like?

JOHN: I don’t know her that well.

MANDY: Roses are a favorite ... a bit presumptuous. How about poinsettias?

JOHN: Perennials might give the wrong impression.

MANDY: Too long-term?

JOHN: Yeah, it’s hard to say.

MANDY: This is complicated. How about petunias? They’re pretty without being presumptuous, smell nice, and in 3 days you throw them out. Sound like what you’re looking for? (pause) Sorry, we’re all out of petunias.