Agatha Christie’s Poison Pen

_{Agatha Christie at her home Greenway House in Devon in 1946, Courtesy Popperfoto/Getty}

“Give me a decent bottle of poison, and I’ll construct the perfect crime.“
Agatha Christie

“Poison has a certain appeal,” wrote Agatha Christie in They Do It With Mirrors, “…it has not the crudeness of the revolver bullet or the blunt instrument.” Death by poison is more frequent in Christie’s world than in the works of any other mystery writer. More than thirty victims fall foul to a variety of toxins (while others survive attempted poisonings). Christie’s knowledge was extensive, a result of her work as both a nurse and a pharmacy dispenser during both World Wars. – Anne Harrison, Owlcation Feb 14 2017

Works where plants and flowers play a significant role

Plants and flowers occur frequently as a plot device in her works and are a common source of toxins:

_{Infographic Courtesy of Garden Collage Magazine}

Sad Cypress – an important clue lies in the fact that a specific variety of rose has no thorns.
Yellow Iris
How Does Your Garden Grow? – an important clue is that the edging on a flower bed is incomplete.
The Yellow Jasmine Mystery – A murder victim left a cryptic clue of “yellow jasmine”. At first investigators were distracted by the yellow jasmine flowers in the garden but later Poirot learnt that it was the name of a powerful but uncommon alkaloid.
Nemesis – in the garden of the Old Manor House, the remains of the old greenhouse is covered with polygonum baldschuanicum. Miss Marple says that this plant grows fast, and is useful if one wants to hide something. It is later revealed that there is something buried underneath the remains of the greenhouse.
Sleeping Murder – there is a whole chapter (ch. 18) named after “Bindweed”. Miss Marple is very concerned about the presence of bindweed which has roots which go very deep. Later in ch. 23 she also mentions bindweed to talk to Inspector Primer as symbolic of events which reach back far into the past.
The Blue Geranium – A murder victim is warned beforehand that a “blue geranium” means death.
The House of Lurking Death – The house Thurnly Grange has a greenhouse. In it grows a castor oil plant.
A Pocket Full of Rye – Taxine is a poison that can be found in the yew tree. Rex Fortescue, who lived at Yewtree Lodge, died of taxine poisoning. Can there be a connection?
The Herb of Death – Foxglove leaves are mixed with sage in the stuffing of a duck.
Greenshaw’s Folly – Miss Marple visits the garden at Greenshaw’s Folly, and sees that whoever was weeding on the day of the murder had pulled up plants as well as weeds. She specifically mentions alyssum, saxifrage, cytisus and thimble campanula. – Agatha Christie Wiki