Ok story for these three is Rogue accidentally bleached one of Fro's two onesie frog costume (his main one) in the wash and he was broken hearted, so Fro gave him the flower to cheer Rogue up and he thought it was so pure and precious.

This was later in a situation where Sting was literally seconds away from dying and/or losing his dragon slayer magic. Rogue was getting payback over the flower.