Eva Evergreen and the Cursed Witch (Eva Evergreen #2) by Julie Abe

From Little, Brown Books for Young Readers 

In this thrilling sequel to Eva Evergreen, Semi-Magical Witch, Eva must put a stop to the violent Culling or risk the fate of Rivelle Realm forever--perfect for fans of Kiki's Delivery Service.

From this day forward, we will believe in the impossible.

Eva Evergreen has fulfilled her dream of earning the rank of Novice Witch, and discovered the chilling truth behind the mysterious Culling -- the violent magical storm wreaking havoc across Rivelle Realm.

Revealing the truth, however, proves to be a difficult task and soon the culprit is at large. To make matters worse Eva learns what might be the horrible truth behind her pinch of magic and her mother's own mysterious connection to the Culling and rogue magic.

With her spirits at an all-time low, Eva must muster up the courage to prove her mother's innocence and learn to believe in her own magic, if she wishes to put a stop to the Culling once and for all.