3 roses stand for I love you while 5 (at least in the Philippines) meant "I love you very much". A dozen may indicate that they have more money to spend and they like to spend it on you :-). But the first time my spouse (while we we still dating) gave me flowers, he gave me 2 roses. I had to ask him what 2 stands for. He said, with a straight face, "2 for 5 dollars".
