Is the Holiday really a Hallmark invention? I had always assumed that it was one of those that was rooted in Pagan tradition, what with this Elfin creature flying around casting love spells and such.
As far as the dead flowers, there is a trick where you hang them upside-down overnight. They will still die, but they will be taxidermied. That is that they will remain crisp and hold their natural shape instead of wilting away and falling apart.