Into the tall, tall grass / by Loriel Ryon.

Enhanced descriptions from Syndetics:

A girl journeys across her family's land to save her grandmother's life in this captivating and magical debut that's perfect for fans of The Thing About Jellyfish .

Yolanda Rodríguez-O'Connell has a secret. All the members of her family have a magical gift--all, that is, except for Yolanda. Still, it's something she can never talk about, or the townsfolk will call her family brujas --witches. When her grandmother, Wela, falls into an unexplained sleep, Yolanda is scared. Her father is off fighting in a faraway war, her mother died long ago, and Yolanda has isolated herself from her best friend and twin sister. If she loses her grandmother, who will she have left?

When a strange grass emerges in the desert behind their house, Wela miraculously wakes, begging Yolanda to take her to the lone pecan tree left on their land. Determined not to lose her, Yolanda sets out on this journey with her sister, her ex-best friend, and a boy who has a crush on her. But what is the mysterious box that her grandmother needs to find? And how will going to the pecan tree make everything all right? Along the way, Yolanda discovers long-buried secrets that have made their family gift a family curse. But she also finds the healing power of the magic all around her, which just might promise a new beginning.