The Salamander Spell: 12/21/15
The Salamander Spell by E.D. Baker is the 5th of the Frog Princess series. It's a prequel that shows the days leading up to the family curse changing Princess Emerelda's grandmother. It's also about how Emerelda's mother, Chartreuse became queen and how unexpectedly, Grassina discovers that she is in fact, the Green Witch.
But here's the thing. Grassina's story has been peppered throughout the previous three books. Book three, Once Upon a Curse even sends Emerelda back in time to discover the roots of the curse first hand.
Basically by now I'm done with Grassina and Heywood. I don't care about how he got cursed because I know enough about the family back story to fill in the blanks myself.