Hour of the bees / Lindsay Eagar.

Enhanced descriptions from Syndetics:

What does it mean to be fully alive? Magic blends with reality in a stunning coming-of-age novel about a girl, a grandfather, wanderlust, and reclaiming your roots.

Things are only impossible if you stop to think about them. . . .

While her friends are spending their summers having pool parties and sleepovers, twelve-year-old Carolina -- Carol -- is spending hers in the middle of the New Mexico desert, helping her parents move the grandfather she's never met into a home for people with dementia. At first, Carol avoids prickly Grandpa Serge. But as the summer wears on and the heat bears down, Carol finds herself drawn to him, fascinated by the crazy stories he tells her about a healing tree, a green-glass lake, and the bees that will bring back the rain and end a hundred years of drought. As the thin line between magic and reality starts to blur, Carol must decide for herself what is possible -- and what it means to be true to her roots. Readers who dream that there's something more out there will be enchanted by this captivating novel of family, renewal, and discovering the wonder of the world.