I would do a white border the same size as the current white. Then I would add a a 1/4" or 1/2" of either the floral or the pink then finish with a wider green (if you have enough fabric to do that). I would then bind it in either the pink or the same green so you don't even see the binding.
I find the best thing to do is put it up on the wall with straight pins - pin in border options and walk by for a few days changing as you go. You will end up with only one obvious solution in the end. The one that finally makes you say "I love that!" That usually comes to me within 24 hours...