I like Amy Stewart’s writing style. It informs and entertains at the same time. She has written a number of books on plants, worms and insects, as well as historical novels. I have read most of her books including Wicked Plants: The Weed That Killed Lincoln’s Mother and Other Botanical Atrocities (Algonquin Books).
While living in Eureka, California, Stewart and her husband ran a bookstore. She also had a poisonous plant garden at her home. She grew many of the plants listed in “Wicked Plants” in her garden. An article about Stewart’s garden in the New York Times, which you can read online, gives you a glimpse of Stewart’s personality.
In addition to writing books, Stewart is also an entertaining speaker, having spoken at local master gardener seminars over the years.
Wicked Plants was released in 2009 but is still relevant to gardening today. I was aware of some of the poisonous plants on her list, like oleander and castor bean, but others came as a complete surprise. Some, like spurge, which contains poisonous sap, are not covered in the book, nor does Stewart write about poison oak and poison ivy.
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I was surprised to find betel nut on their list of evil plants. I’ve always loved the song “Bloody Mary is the Girl I Love” from the South Pacific musical. Bloody Mary always ate betel nut. I had no idea the nut was so addictive. Native to India and parts of Asia, this plant is a Schedule 4 poison in the United States, meaning it’s only available by prescription.
The World Health Organization has warned against chewing betel nut, the seed of the fruit of the areca palm. Betel nut not only gives an energy boost, but also rots the user’s teeth. If you’re in a country where betel nut chewing is common and someone smiles at you and has no teeth, you know why. The sidewalks are also likely to be covered in red marks from users spitting out the betel nut juice.
The nightshade family is large and includes many plants in our vegetable gardens, such as potatoes, aubergines, peppers and tomatoes. Parts of these plants are of course edible, but eating the leaves and stems can lead to major problems, including stomach upset. Eating raw potatoes can cause similar ailments, but cooking them deactivates the harmful chemicals. Potatoes that develop green spots from exposure to light are also mildly toxic to some people. It is therefore advisable to store potatoes in the dark.
Stewart has a special interest in Nicotiana, known as the tobacco plant. Native Americans smoked tobacco leaf 2,000 years ago. European explorers brought this New World plant to Europe. Today, tobacco is grown on nearly 10 million hectares worldwide and kills 5 million people annually. Nicotiana belongs to the nightshade family and, as we now know, is highly addictive.
So what was the weed that killed Lincoln’s mother? She died of what was then called milk fever. The disease is caused by the white snakeroot (Ageratina altississima), which grows wild in wooded areas of the United States. Cattle would graze on it and transmit the fever to humans through their milk and meat. Lincoln’s mother was ill for a long time and died when he was 9 years old.
The opium poppy (Papaver somniferum) is one of the few evil plants with seeds that we can buy. Many people grow these poppies in their home gardens as the flowers are beautiful. Poppy seeds are used for cooking. However, the seed pod is the source of opium from which we derive morphine, codeine and other painkillers. When I visited Turkey I saw many fields of white poppies but the seed pod could only be sold to the government. The orange California poppy (Eschscholzia californica) is not related to the opium poppy.
Stewart provides many anecdotes and examples of how these weeds and native plants have caused disease and even death. Jonathon Rosen’s illustrations are excellent. This book is easy to read and I suggest you put it on your wish list.
To learn more about evil plants, register for the free Napa Library talk on “Danger and Romance in Your Garden” by Napa County Master Gardener Cindy Watter on Thursday, October 6 (details below) .
Become a volunteer master gardener! UC Master Gardeners of Napa County is now accepting applications for the Class of 2023. Click the Join Us button at napamg.ucanr.edu to read the information brochure and register to attend a mandatory applicant information session. Applications are due by 5pm on September 30th.
Library Talk: UC Master Gardeners will be hosting a talk on “Danger and Romance in Your Garden” via Zoom on Thursday, October 6 from 7-8pm. Many popular landscape plants are also poisonous. Learn more about these dangerous beauties in this free lecture. Sign up to get the Zoom link.
Food cultivation forum: Join UC Master Gardeners of Napa County for a free forum on Cover Crops in Depth on Sunday, October 9 from 3-4 p.m. via Zoom. Register to get the Zoom link: https://napamg.ucanr.edu/?calendar=yes&g=9191.
Guided tree hike: UC Master Gardeners of Napa County will host a guided tree walk in Napa’s Fuller Park on Tuesday, October 11 from 10 a.m. to 12 p.m. Meet at the corner of Oak Street and Jefferson Street. The number of participants is limited to 12 guests. You must register in advance and each guest must register separately.
Penny Pawl is a UC master gardener from Napa County