Jill Johnson on the plant inspiration behind Devil’s Breath

I’ve always been better with plants than people and I tend to name people after the plants they most resemble. Father first suggested I do this when I was a child, because I find it difficult to recognise faces and remember names…

Eustacia Rose is a Professor of Botanical Toxicology who lives alone in London with only her extensive collection of poisonous plants for company. She tends to her garden with meticulous care. Her life is quiet. Her schedule never changes. Until the day she hears a scream and the temptation to investigate proves irresistible.

Through her telescope, Professor Rose is drawn into the life of an extraordinarily beautiful neighbour, Simone, and nicknames the men who visit her after poisonous plants according to the toxic effect they have on Simone. But who are these four men? And why does Eustacia Rose recognise one of them?

Just as she preserves her secret garden, she feels inexplicably compelled to protect her neighbour, but Eustacia soon finds herself entangled in a far more complicated web than she could ever have imagined. When her precious garden is vandalised and someone close to Simone is murdered with a toxin derived from a rare poisonous plant, Eustacia becomes implicated in the crime.

After all, no one knows toxic plants like she does…

Flashback to 1995. I was in a plant identification seminar during my ornamental horticulture degree at university. The plant samples were lined up on the main table in front of us. Some were cuttings in jam jars half filled with water, others were entire plants in pots. We listened as the lecturer described the habits of each sample and explained the taxonomy of their Latin names.

But within minutes we’d stopped listening because we couldn’t quite believe what we were seeing. We thought the lecturer was messing with us. It looked as if she’d balanced a pair of shiny plastic lips on the leaves of one of the plants. The kind you can buy in joke shops. Seeing our quizzical expressions, she smiled and began to describe the Psychotria elata. An unusual tropical plant native to Brazil with bright red glossy bracts that have an amazing resemblance to full red lips.

I have never forgotten that seminar. It’s stayed with me for decades and on a visit to the Alnwick Poison Garden in Northumberland years later, I was hoping to see the plant again because, although it isn’t poisonous, it does contain the powerful hallucinogenic chemical dmt. It was on that visit, whilst listening to the gruesome murders by plant poison being told to us by our guide, that the seeds of a story began to germinate.

Murder by plant poison is an oft used trope in crime fiction. Agatha Christie (my hero) was a master of this art. But what if my protagonist was a professor of botanical toxicology? And what if her collection of poisonous plants was vandalised? And then what if somebody dies from a toxin extracted from one of those vandalised plants?

So many what ifs were rolling around my mind, so many exciting possibilities. I had the beginnings of a story, a protagonist and, thanks to that plant identification lesson at university years before, I had one other character – a beautiful Brazilian woman with full red lips, who had a mesmerising and addictive effect on my protagonist.

It was then that an idea occurred to me. Some people have a mesmerising effect, others are toxic and perhaps my botany professor categorises people according to their level of toxicity, just as she does with the plants in her collection. And perhaps she is the kind of person who finds names difficult to remember and so gives them nick names after the plant they most resemble.

And this was how my other characters were born, my toxic, irritating and beneficial characters were all based on plants that had an effect on either my professor or my Brazilian woman. It was a fun idea that played to my two loves – plants and writing – and therefore the book would undoubtedly be a doddle to write.

How wrong was I.

Crime fiction is not a doddle. It’s a complicated puzzle with many messy pieces. It’s an embroidery with intricate thread work that is connected then disconnected, then connected again until everything is tied up neatly at the end. Unless you’re writing a series, in which case, one or two threads must be deliberately left loose, preferably with hooks attached.

Devil’s Breath by Jill Johnson (Black & White publishing, £16.99)