User blog:Yukosera/Need help here

I've been trying to get a alt sprite from my Vine Dragon and Black Dragon, but I can't seem to get an egg that contains it. Is this a problem, or does it have to be bred with the same breed of dragon? Also I try breeding my Vine Dragon with other dragons, but what comes up is the father's egg breed. Why can't I get a Vine Dragon, from my orignal one?