My girlfriend is trying to remember a film she saw a few years back. The details are sketchy, though. She thinks it was about a woman who was killing people using poisonous plants. The lead characters tried to escape at the end by running through the plants (they didn’t know they were poisonous), and one of them dies.

She thinks there’s a groundskeeper buried in the garden. She seems to think it might be a hospital or asylum, and there might be a girl trapped in a well at the beginning.