Kingdom of Thorns by Katherine Macdonald

Cursed at her Christening, Briar is doomed to prick her finger on a spinning wheel on her seventeenth birthday and plunge her kingdom into eternal slumber. Less than enthused about her fate, she fights to break it, but a hundred years later the kingdom lies at the centre of a forest of thorns. The curse is complete and only true love’s kiss will break it.
Volunteering in the place of his brother, Leo is determined to brave the enchanted forest and attempt to end the hundred-year-old curse. If he fails, the dark fairy, imprisoned within the Kingdom of Thorns, will be unleashed upon the world and a kingdom will fall to ruin.
Guided by a mysterious young ranger named Talia, he sets off on his quest, but the darkness isn’t the only thing that grows in the woods, and Leopold finds himself locked in a bitter fight for his life, his sanity… and his heart.