The poison garden built by Jane, Duchess of Northumberland, has inspired a trilogy of young adult novels, starting with "The Poison Diaries."
It was Jane - the real force behind turning a ruined garden at Alnwick Castle in northern England into a huge tourist attraction - who came up with the character of Weed, the young man able to communicate with plants.
And in the novel, the teenage Weed turns up at a ruined monastery near the end of the 18th century and meets its residents: Jessamine, 16, and her widowed father, renowned for his healing skills with plants that he grows or finds.
Of course there is romance and tragedy in the story, but readers will also note that at least two plants are main characters: the poisonous shrubs belladonna and oleander.
In real life, Jane sees the walled and locked poison garden at Alnwick as educational, and she thinks stories are the best way to teach youngsters.
"We are enlarging the poison garden, which is so popular," she said in a recent telephone interview. "It captures people's imagination. They all grow in their gardens, and people have no idea about their capacity to kill or cure people."
In Scotland 1980s excavations of the ruins of Soutra Aisle, a monastery-supported hospital, showed that amputations were carried on in the 1400s, Jane said.
"They found sponges with herbs that had come from Malaysia through Venice to Scotland," she said. "They had henbane, hemlock and opium in the right combinations to keep someone unconscious for 48 to 82 hours - exactly how long it takes to cut off an arm or a leg and for the body to start healing."
With a special license to grow plants like marijuana and the coca that cocaine comes from, Jane believes the poison garden can convince young people that drugs today might be very different from what their parents or grandparents experimented with in the 1960s.
"Plants today are gene modified and can be much more dangerous," she said. "We tell the kids they are playing Russian roulette. It's a very powerful message."
Of course, in the era of Weed and Jessamine there were no tests to determine whether deaths were caused by poison. In Italy in the 17th century, 500 women killed their husbands and lovers with strychnine, Jane said, sometimes by putting it in their clothing.
"The same plants used to kill could be used to cure," she said. "For example rosemary could be used to ease childbirth, but it could also cause abortions."
In the book, the health secrets were lost when the monasteries were destroyed by the crown. But Jane said women who knew these recipes were persecuted as witches, especially when someone they tried to help died.
And "The Poison Diaries" could have happened at Alnwick, which has the ruins of an abbey, she said, and historic dukes always had apothecaries like Jessamine's father to help cure people in the area.
Thus it was the setting that inspired the duchess to come up with the young man who talked with plants.
"He had always been called Weed in my mind," Jane said. "That was nonnegotiable. I wanted people to empathize with Weed."
And the branch of HarperCollins, the publisher that liked Jane's idea, had author Maryrose Wood as soon as she heard the concept: "It's a boy who can communicate with poisonous plants." That was even before Wood knew that researching the book involved a trip to England and touring with the duchess.
"I was fascinated," she said in a telephone interview. "If a human being could get into the consciousness of these plants, it would be a great jumping off place for a book.
"I'm a gardener myself and always gravitated toward growing herbs," said the New Yorker. "People have always grown herbs to make medicines, cosmetics and for ritual uses."
With the duchess and a local scholar Wood viewed Soutra Aisle.
"Imagine us on a freezing cold hilltop in Scotland. It was wonderfully spooky," she said.
And the result is the book for readers aged 12 and up, with the second volume due out next summer.
"We grapple with big moral questions and are interested about our relationship to the environment - a question that's evolved a lot over the course of civilization," said Wood. "We have a new sense of how dependent we are with the natural world. We think of ourselves as being the people, the sentient ones. yet without plants where would we be?"