Writer exposes plant world's 'criminal element'

Amy Stewart is fascinated by plants behaving badly — what she calls "social misfits" of the horticultural world that can "kill, maim, intoxicate and otherwise offend."

In her new book, "Wicked Plants: The Weed That Killed Lincoln's Mother & Other Botanical Atrocities," the Eureka, Calif.-based writer offers up more than 200 examples of botany's bad boys and girls, along with anecdotes — and fun, if sometimes horrific, facts — that place the plants in the context of history, legend and science.

Stewart recently answered a few questions about the plant kingdom's "criminal element."

Q: Please explain your insatiable fascination with the dark side of the horticultural world.

A: I'm interested in these plants as characters, and the most interesting characters are somehow flawed. I like outcasts and miscreants. Plenty has been written about all the pretty plants we love. I thought it would be fun to explore the plants we hate. Plants that have started wars, been used as weapons, plants that behave badly — they're interesting because they stir up trouble.

Q: How did you decide which of the many botanical atrocities to include?

A: I was always looking for a plant with a good victim. I needed to know where the bodies were buried. There had to be a human story — a serial killer, an unfortunate couple on their honeymoon, an unlucky gardener — for me, this book was all about the people. If there wasn't a specific interesting human (or animal) story that illustrated the plant's evil powers, I didn't include it. It's a highly selective book in that way.

Q: Most gardeners probably have at least one of these lowlifes in their yards — and maybe more. Are people surprised to learn that their gardens can kill them?

A: You know, I think that what people need to remember is that not all plants are food. When you walk into the drugstore, you'll see all kinds of things for sale that are not food for you. "... I don't think people walk in and go, "Oh wow, this drugstore could kill me." They just understand that some of the things for sale are food and most of what's for sale is not food. But with plants, people have this weird idea that anything growing in the ground was put there just to make us happy. And that's so not true — many of these poisons and painful barbs were developed specifically so the plant can defend itself against getting eaten.

Q: Not to mention their pets.

A: Absolutely. I definitely included some pet poisons in the book. Sago palms are very toxic for dogs, and lilies for cats. If you have a pet that gets into everything, you should definitely take a look around your yard.

Q: Sounds like some of the biggest evildoers are in the solanaceae family. We meet the relatives throughout the book, and many are nasty in some way. How big is this group?

A: That's the nightshade family, and you're right — there are a lot of wicked plants in that group, from datura, a beautiful white trumpet-shaped flower that is a hallucinogen, to atropa belladonna, or deadly nightshade, which definitely lives up to its name. Then again, the nightshades also include tomatoes and potatoes, which I couldn't live without. There are actually several plant families that, like our own families, have good guys and bad guys — the carrot family, for instance, has carrots, dill and so forth, but also poison hemlock.

Q: How many of these killers are you growing in your own garden? Are they locked up?

A: I have a poison garden filled with these wicked plants. They're not locked up, but it's a small garden off the kitchen that is not real accessible from the front or the back. I grow hemlock, oleander, monkshood, tobacco, foxglove, datura, hellebore — it's actually a lovely garden, but totally deadly.

Q: Rounding up all the anecdotes in the book, what's the body count?

A: Oh, good question. There's really no way to know how many people have been killed throughout history by these plants, but it's in the hundreds of millions. Tobacco alone is responsible for almost 100 million deaths — and that's just since we started keeping track.

Q: Besides being entertained by the sleuthing and storytelling, what do you hope readers take away from your work?

A: I just want people to appreciate that we have a long history with plants, and they've been with us in some important moments in history. I think people who are not total plant geeks don't realize that a garden can be more than pretty scenery — it can tell a story. I grow the weed that killed Abraham Lincoln's mother (white snakeroot; Nancy Hanks Lincoln is believed to have consumed milk from a cow that had eaten the plant). The plant that killed Socrates (poison hemlock). These are powerful, interesting plants. Nature is powerful. I want people to remember that.

Q: It must have been fun doing research in such places as the Alnwick Poison Garden and the Chelsea Physic Garden, both in England. Where else did you go to turn up these tales of wicked plants?

A: The USDA Poisonous Plant Research Center in Logan, Utah, was totally fascinating. They're mostly researching plants poisonous to livestock, but there are a lot of great spinoffs to that research — interesting medical breakthroughs. Like most medicines, a little can heal you and too much can harm you. Many of these poisons have some potential medicinal benefits, too.

Q: You're traveling on a book tour with an antique leather carrying case. What's inside?

A: Wicked seeds, leaves, roots, that sort of thing. Some plants from my garden and some that I bought on eBay, which turns out to be a great place to get weird plants. It is a very cool old case filled with glass bottles that once held poison antidotes. Quite creepy.

Q: Seems like that would be a real red flag for airport security. Have you had any odd looks?

A: Nope. They always take it out and look at it, but I explain that it's an antique case with glass bottles and no liquids or gels. That's it.

Q: What's the most fascinating aspect of the plant kingdom's dark side? You mention horticultural lowlifes that are just plain offensive.

A: I like really offensive plants. I have a section on plants that explode, plants that catch on fire, plants that stink of rotting corpses, and, of course, plants that take over — some invasive plants that are so rampant they're actually quite terrifying.

Q: Have you personally tried any of the mind- or mood-altering plants or plant parts?

A: Sure, but I didn't inhale. Actually, I do include illegal and intoxicating plants, from cannabis to opium poppy to some more obscure ones you might not have heard of. Here's one I'll admit to: absinthe. It's flavored with wormwood, which contains a compound called thujone that can cause seizures. But as it turns out, very little thujone survives the distillation process. Absinthe's wicked reputation mostly comes from its very high alcohol content, not the herbs used to flavor it. It's a very herbal, almost medicinal-tasting drink, but with twice as much alcohol as gin or vodka, so a little goes a long way.

Q: And how was that?

A: Green and boozy. What's not to like?