This Poison Heart by Kalynn Bayron

Briseis has a gift: she can grow plants from tiny seeds to rich blooms with a single touch.

When Briseis’s aunt dies and wills her a dilapidated estate in rural New York, Bri and her parents decide to leave Brooklyn behind for the summer. Hopefully there, surrounded by plants and flowers, Bri will finally learn to control her gift. But their new home is sinister in ways they could never have imagined–it comes with a specific set of instructions, an old-school apothecary, and a walled garden filled with the deadliest botanicals in the world that can only be entered by those who share Bri’s unique family lineage.

When strangers begin to arrive on their doorstep, asking for tinctures and elixirs, Bri learns she has a surprising talent for creating them. One of the visitors is Marie, a mysterious young woman who Bri befriends, only to find that Marie is keeping dark secrets about the history of the estate and its surrounding community. There is more to Bri’s sudden inheritance than she could have imagined, and she is determined to uncover it . . . until a nefarious group comes after her in search of a rare and dangerous immortality elixir. Up against a centuries-old curse and the deadliest plant on earth, Bri must harness her gift to protect herself and her family.