Gardening with a Ghost by Amanda Meuwissen

Peter Thorne has a secret—he can bring the dead back to life.

When Peter’s mother died, she passed him the touch of life and made him promise to use his abilities wisely. Unable to bring her back and afraid of being caught or causing too much imbalance in the world, Peter vowed to use his gift only on plants. After all, with people, sometimes dead is better.
Or that is what Peter thinks until he takes a gardening job at Benes Manor. The mystery of a missing girl, an old gothic home, and the whispers and tempting caresses of a ghost in his room lead him to delve deeper into his powers than ever before. Perhaps he can find the missing girl and the origins of his ghostly visitor, if only he knew who to trust—and who and what to touch.