Zoë Schlanger. Photo by Yael Malka
By Jon Letman
Environmental journalist Zoë Schlanger, a staff writer for The Atlantic, had been covering the climate crisis for several years when she became aware of a creeping sense of doom. Seeking an escape from the onslaught of heavy news stories, she started spending her lunch breaks reading botany journals. Her fascination with academic publications, combined with her long-time affinity for her own urban jungle of houseplants, spurred a journalistic deep dive into the world of plants.
As she waded further and further into the scientific weeds, she undertook a quest to explore plant life, not as the passive, potted type or even the garden variety oxygen-producing, food and medicine-providing, all important botanical life forms we depend on for survival, but as sensitive, deliberate, and — in their own way — intelligent beings.
Zoë’s quest led her on a five-year global journey, interviewing scientists and hiking with botanists and conservationists from the moss-drenched rainforests of the Olympic peninsula and Chile to the caves of Puerto Rico, cliffs of Hawai‛i, and beyond.
The result was The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth, a New York Times best seller that illuminates how plants can react to specific sounds and tones, count, remember, and correct errors in judgement. Examining the science of how plants communicate underground, mimic one another, and can recognize and give preferential treatment to their closest kin, Zoë introduces her subjects not just as sentient beings, but as highly evolved individuals, worthy of reverence.
Courtesy of HarperCollins
She writes, “there is something sacrilegious about felling a four-hundred-year-old tree for decking—or even a thirty-year-old pine for toilet paper. What did it take for that tree to live through those years, make thousands of leaves each spring, store sugars through the winter, turn light and water into layers and layers of wood? It is hard to underestimate the drama of being a tree, or any plant. Every one is an unimaginable feat of luck and ingenuity. Once you know that, you can’t unknow it. A new moral pocket has opened in your mind.”
NTBG Bulletin editor Jon Letman spoke with Zoë about her book. Their conversation was edited for length and clarity.
Jon Letman: How does your book, which questions assumptions about plants, offer a new understanding of plant life?
Zoë Schlanger: Those of us who were raised with the Western European thought tradition were not raised to view plants as animate, sensing, decisioning beings. Through speaking to botanists when botany is undergoing a bit of a revolution thanks to technology, also thanks to changing perceptions over what questions can be asked of plants, I’ve taken on an entirely new perspective of the organisms as highly active and highly sensing.
They’re capable of including complex variables in their decision making and they’re oriented not just towards basic survival, but towards thriving and optimizing conditions for their offspring. All these traits that we think of as animal oriented are actually very much present in plants, but in entirely different, novel ways.
How has writing this book changed your relationship with plants?
I have a completely new relationship with the plants in my life. I have a lot of house plants but there was an uncanny moment in the process of working on this book, of looking at my house plants and wondering if I was keeping them like animals in cages. I had just been researching the world of plant communication and root to root signaling and I felt somewhat soothed by understanding these are plants mostly reared in nurseries for generations and may have lost a lot of their proclivity for complex defense systems or communication.
Now when I walk among plants I feel very aware of this elaborate plant drama going on around me and really see plants as individual organisms with separate lifestyles and distinct biological personalities some might say. It’s not just this wash of green anymore, but it’s a certain respect and admiration for the individuality of each plant.
I suppose that makes visiting a botanical garden, a forest or a city park, a different experience altogether.
Absolutely. It’s a much more enlivening experience. It has definitely re-enchanted my experience of plant life. That’s almost too mystical a word because it’s also all based on hard science. I’ve been given the knowledge and facts to see plants for what they are.
You wrote about a controversial 1973 book called The Secret Life of Plants. How did that book make your research more difficult and is it still impacting how people think of plants?
That book cast a very long shadow on botany and because so much of it couldn’t be verified as real science, a lot of the main sources of scientific funding became a bit shy about funding research into plants as behaving organisms. Any research with even a whiff of this idea of plants as organisms that have behaviors was more or less pushed underground for about 30 years. It’s only been in the last 15 or so years that taboo has worn off. Also, technology has gotten so good that certain things that couldn’t be verified before can now be very rigorously studied.
At almost every book event I do, someone asks me about plants enjoying music or talking to plants or plants being able to read our thoughts which were all ideas posited in The Secret Life of Plants. It shows how powerful some of these conceits can be in the popular imagination. It also made some scientists more wary about speaking to me about the idea of plant intelligence. But I assured scientists that I was focusing only on peer reviewed research and would treat their work rigorously.
How has your book been received by botanists and the broader scientific community?
It’s been really positive. I’ve been heartened by the fact that a lot of the scientists in the book, and scientists that I now meet have appreciated the book and felt that I treated their views and work fairly. It’s so interesting because this idea and debate around plant intelligence, agency, and consciousness is quite separate from the actual science being done.
In terms of the science, I was just describing research that is mostly accepted by the scientists — certainly those who did it — and they may have a different view on how to interpret it. But I think these are questions scientists are asking themselves too and I think they appreciate a venue for that to be handled in a rigorous, scientific way.
You wrote that generally speaking, “humankind knows very little about plants.” How do you see people as being uninformed about plants and how can that be changed?
Of course this doesn’t apply to all people. Those of us who received a Western European thought tradition were raised in this atmosphere of thinking of plants as passive, inert beings that were mostly just instruments, objects for human consumption and use and nothing more than a material that makes our lives go. Many cultures understand how misguided that is. Certainly, Indigenous science and cosmology from all over the world recognize plants as primary organisms and humans as secondary or even tertiary ones because of our absolute dependence on plants. The air we breathe and every single molecule of sugar we’ve ever consumed is all thanks to plants and so that total dependence is a scientific, obvious fact and one that somehow has not culturally sunk in for a lot of people, but I do think that’s changing.
There’s something within all of us that recognizes that’s a misalignment of belief. These living creatures that are so expertly, spontaneously, and with great complexity, navigating their world and surviving in every possible climate on Earth and — despite unbelievable odds— flourishing, are not simply just inert material like you might imagine a stone.
In your book you ask how something without a brain coordinates a response to stimuli. “Of course, a plant doesn’t have a brain,” you wrote, “but what if the whole plant is something like a brain?” to which one plant biology professor you spoke with said, “I think you’re right. I just don’t talk about it.” Did you meet other scientists open to the idea of plant intelligence?
Most scientists are very specialized and are working on one small system within plants or one small interaction that plants have with other plants. They’re busy doing their research, but many of them can’t help but wonder what the bigger implications are. I think that the era of thinking about network intelligence as a legitimate field of study has really opened up the mind of academic fields to be receptive to the idea that perhaps there are other ways of processing information that are not necessarily brain-centric.
I spoke with a researcher who has been fixated on the idea of network intelligence since the late 1970s. He explained that from an evolutionary theory perspective, it makes sense that humans developed a centralized compact decisioning center in a brain because we have to run across the landscape to forage for food and run from threats. You need something compact to do that, but it also makes humans very vulnerable. You can’t suffer a blow to the head and continue surviving, whereas plants evolved in a totally different regime, rooted in place and modular so they could lose limbs. They’re made of repeating almost identical parts, and one can be lost without hugely detrimental effect. There was no need for a compact portable decisioning center for plants.
If you take that view, whatever system they had would look quite different. It’s still an open mystery how it’s possible that plants can transfer an audio signal into a decision or a pinch on one part of their body into a response in another part of their body.
Photo by Gloria Dickie
In 2017 you participated in NTBG’s Environmental Journalism program. How did the program influence your reporting, and did it play a role in you writing this book?
Yes, that program changed my life forever. I came in as an environment reporter, mostly interested in air and water pollution, which I still cover. But it definitely opened my eyes to botany. It put me in touch with the thing that is now very clear to me — that I love speaking to botanists.
I think it was specifically the days spent with [former NTBG botanist] Steve Perlman that did that for me. Hiking around the Nā Pali (cliffs) with him, hearing about his intense love for individual threatened species opened part of my brain to this idea that all plant life is worthy just for the fact that they’ve evolved to this point and have a right to exist simply because they exist now.
That was the nudge I needed to think of plants not just as passive instruments in the human world, but as biological entities that are the products of long histories of creative biological experimentation on the part of evolution and have intrinsic value just for themselves. This book wouldn’t be here if I hadn’t been an NTBG Environmental Journalism fellow, I think.
You have described how reporting on the climate crisis was taking a heavy mental toll and how that led you to focus on plants. Has your reporting on plants impacted the way you cover climate change now?
I think I have a greater attachment to the material stakes of climate change on the non-human world than I did at the start of this. Often what I’m covering are macro climate issues — climate policy, international climate negotiations, climate science from a big picture perspective. But always at the back of my mind is what all of this means for the human world, but also the non-human world and what it means for biodiversity loss. That is central to my concern with plants.
I have a greater sense of what is at stake. But it has also been a humbling experience. The history of all plant life is that it has managed to flourish in every possible condition, and the future of plant life is tragically unclear at this point due to human-caused climate change. But there is a future for plants. We just don’t know what it looks like yet.