Thanks for the link, MacLeod
I was under the impression that you send cards and flowers only to the person you love? Do you send them to friends and people you just like, too?
This site might be interesting for some of you: it's the good old Victorian Flower Code: http://www.languageofflowers.com/flowermeaning.htm
You can send Valentines to anyone. It's usually reserved for romantic gestures but you can also send them to friends, relatives, etc. Although, usually only women send non-romantic ones to friends, mothers to children, etc. I think, in the US, if a male friend sent another male friend a Valentine card, as a friend, (and not in a joking manner), that friend would be weirded out.