Poisonous plants lurking in the border


When I started writing my Maybridge Mysteries series, the opening scene for the first book had been in my “ideas” file for years. And I already knew that my main character, Abby Finch, was going to be a gardener.

I had a title in my head – A Rose for the Dead. Since I envisaged a series, it seemed like a really good idea to have a plant name in all the titles.

However, since it appears to be the convention for cozy crime is to have either murder, or death in the title, my publisher, Joffe Books, changed it to Murder Among the Roses.

Having spent thirty years having my working titles changed by my publisher, this didn’t come as a huge surprise. I still prefer mine but whatever sells the book. And I had my flower.

Since the use of plants was going to be part of the branding of the series (next up this autumn, Murder With Mistletoe), I fell down the research rabbit hole looking for plant life that can kill.

Poisonous plants

You know how, when you look for anything online, from a washing machine to hi-top sneakers, you start getting adverts for them all over social media?

I started getting “poisonous plant” prompts on Facebook. My search history might raise a few eyebrows!

poisonous mushroomAstonishingly, poisonous plants are everywhere and it’s not just the ones we all know about. Like the deadly Death Cap mushroom that turns up regularly on cozy crime shows on the television.

I discovered some very disturbing facts about plants we all love and have in our gardens. Did you know, for instance, that you should wear gloves when handling foxgloves, (Digitalis purpurea)?

poisonous foxglovesUsed in heart medicine, they are extremely valuable – my husband took digoxin to help regulate his heart – but they contain toxic cardiac glycosides and can result in severe poisoning.

Here are some in my last garden in Wiltshire. So lovely.

Monkshood (Aconitum napellus) is one of the UK’s most poisonous plants. It grows in damp woodlands, meadows and along ditches in the southern half of the country, but its attractive blue hooded flowers have made it a popular garden plant. It has cultivars in a variety of colours.

Monkshood myths and facts

poisonous monkshoodThere are many stories about monkshood being used as poison. Medea, a Scythian sorceress, tried to use it on Theseus. Athena used it to change Arachne to a spider when she dared outspin the goddess.

A more creative technique for poisoning with Monkshood was carried out by Calpurnius Bestia. He would smear his finger with an extract made from the roots and touch the genitalia of his wives. Once absorbed, it led to their deaths.

And the Roman emperor Claudius fell to aconite poisoning. Needless to say, this is another plant to be handled wearing gloves!

The attraction

poisonous daturaAll species of this beauty, Datura, or Angel’s Trumpet, native to the tropics, are extremely poisonous. They’re also potentially psychoactive – especially the flowers and seeds.

However, Victorian ladies cultivated it in their conservatories and caught drops of the nectar in their teacups for an illicit buzz.

Not everything is what it seems

Cow Parsley

You’re not likely to want to grow hemlock (Conium maculatum) in your garden as the leaves have an unpleasant smell when crushed.   But it is easily confused with cow parsley which has migrated from a hedgerow plant to a garden favourite.

poisonous hemlock


Every single part of hemlock is poisonous. It was the plant that was given to the famous Greek philosopher, Socrates, for his execution.

The toxins in hemlock are alkaloids which cause muscular paralysis, and bring the central nervous system to a halt. So  useful for the crime writer!

Have you ever taken castor oil?

castor oil plant with poisonous seedsThere was a bit of a fuss last year over some castor oil plants in public gardens.

Its attractive leaves and spiky seed heads make it an attractive addition to the garden. But the seeds are full of ricin – famous for the killing the Bulgarian dissident, Georgi Markov in 1978.  I once saw a fine specimen in the garden of Wells Cathedral.

laburnum avenue poisonous

Image by fallonrw from Pixabay

And this is a photograph of the magnificent laburnum archway at Bodnant.

It’s stunning. You once saw these trees in nearly every front garden.

They fell out of favour once it became common knowledge that the seeds – so attractive to children – are poisonous, as is every part of the tree. (Or maybe it was when employing a gardener or maid to sweep up the seeds became a thing of the past!)

It’s another of those that cause respiratory paralysis.

The Poison Garden

Alnwick poison gardenOn my bucket list is a visit to Alnwick and its famous poison garden guarded by iron gates with its skull and crossbones warning. A must for all crime writers!

Are you scared yet?

The first of my Maybridge Mystery series is Murder Among the Roses, available in paperback and eBook.


12 thoughts on “Poisonous plants lurking in the border

  1. Elizabeth Rolls

    I’ve known about foxgloves and various other poisonous/medicinal plants for a while. Writing historical romance means I try to be aware of what might be used medicinally for my characters. Many years ago a friend in Melbourne had a datura growing right outside her bathroom window. And my mother-in-law grew opium poppies in the back garden! Totally illegal of course. I thought about getting some seeds from her, but in the course of reading up on opium for a book I found that you can ingest the drug through your skin when the seed pods ripen. Since I had small boys I decided it wasn’t a good idea. It’s quite amazing what simultaneously dangerous and useful plants are lurking in our gardens.

  2. Elizabeth Bailey

    Absolutely terrified, Liz! I knew a couple of those but – ouch! Every garden a minefield. I’ve had to do the poison research too, but confined to what was known in late Georgian times. Found a very useful contemporary tome on Google Books for that one. I ended up using opium rather than plants per se. I should think you’re going to need that locked garden research too!

  3. Liz Fielding

    Plus all the things that can give you a rash, Liz! And I discovered that, unlike in most of the television adaptations of AG, poison can be a very messy business! Opium sounds like a good way to go…

  4. lesley2cats

    As my murders tend to be unplanned bash-over-the-head ones, I haven’t had to do that much research, but I’ve often wondered about rhubarb leaves. And I’ve always wanted to go to the Alnwick, too!

  5. Rosemary Gemmell

    I love gardening but refuse to grow foxgloves now! We visited the Poison Garden last summer, Liz – fascinating. You’re not allowed to go in without a guide, for obvious reasons. I bought the beautifully illustrated booklet about it from the gift shop afterwards which gives plenty of information and ideas. I enjoyed Murder Among the Roses.

  6. Elizabeth Rolls

    “Please don’t try this at home.” Absolutely. Joanna! I wrote a book some years ago wherein the sticky subject of contraception arose. I did a great deal of research as to what effective methods of contraception were available in 1802. Naturally when I was asked to do a guest blog on some aspect of my research as part of promoting the book I chose that. I made sure to include a warning not to try it at home without advice from a fully qualified herbal practitioner.

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