I quite like all three, but
Violet and
Ivy vie for my vote. I enjoy the long "i" and "v" sounds in both and also the imagery of both. My favorite color happens to be purple, closely followed by green. For myself, I would choose
Violet if it hadn't already been used in my family. I would definitely consider using
Ivy. As far as popularity goes, I feel as though I hear
Violet more often and see it more often in birth announcements.