Learning the Language of Plants

In celebration of their new plantcentric books, Dispersals: On Plants, Borders, and Belonging and The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth, authors Jessica J. Lee and Zoë Schlanger sat down for ranging conversation about emerging science, plant intelligence, culture, memory, botanical belonging, and how our houseplants may influence our thinking.

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Jessica J. Lee: Both of our books center on plants, but come at the topic from a specific angle. Why did plant intelligence capture your attention? 

Zoë Schlanger: Plant intelligence is not an intuitive proposition. As humans we’re terribly biased toward things that have faces and brains. But research over the last two decades—and older work, in the time of Darwin—is finding that perhaps a brain is not a prerequisite for intelligent behavior. I was intrigued by this, I had always been drawn to plants as calming, somehow reassuring companions. They do strike me as very competent, going about their lives with a certain sureness. What I didn’t realize going into this was just how many decisions a plant is making at all times, how much vitality goes into their every phase, and how spontaneous and social they actually are. It brings a certain enchantment to my life now.

JJL: I love this answer. I think it’s interesting that you mention that distance between us and plants, which stems from our tendency to connect with other creatures with faces. Because I think the thing that drew me to the subject of plants out of place was precisely that we pretend this distance exists, and then use really human language to describe plants. And think about them in so many of the same ways we think about people. I couldn’t get this idea out of my head, literally for years… so I had to write a book about it.

ZS: Gorgeous. Yes, I’m thinking about Theophrastus now, who coined the term “heart-wood” to talk about the vulnerable core inside trees. He understood that humans needed metaphors like that to connect to other forms of life, but also that metaphors were more than simply devices, that there really are those threads of connection between us; between our bodies and, say, the structure of a tree. Speaking of which, I loved your chapter on the “plant explorers” which gets into this gritty place of humans layering humanoid language onto plants—perhaps while simultaneously ignoring the humanity of actual humans. You write about David Fairchild, who was responsible for the introduction of so many food plants in the United States: mangoes, hazelnuts, grapes, walnuts, olives, lemons, peaches, persimmons – but that there’s an “uneasy beauty” in the archives of his and other “plant explorers.” These explorers seemed to have an immense curiosity about plants in the places they “explored,” while also having little or no concern for the people in those same places. And yet: These were exciting botanizing adventures. How do you think about your own rapacious interest in plants, and how does it relate to these earlier examples of adventuring botanists? 

JJL: I think one of the big things I wanted to unpack in the book was that troubled feeling of simultaneously being slightly horrified by the way botanical extraction was carried out, while also finding a part of myself wholly enthralled. Like holding the aesthetic appreciation of detrimental plants alongside knowledge of their impact. I wanted to investigate what it might mean to hold both those stories at once, to ask if I could come to a place of… not acceptance of how it was done, but perhaps coming to grips with my own inner, earlier longing for adventure, for what that looked like in the past. Really, it’s about that co-shaping of culture and nature. You actually offer a provocative line, arguing that every thought we’ve ever had was made possible by plants. Can you unpack the ways plants shape us? 

ZS: Oh yes. I meant that very literally. Plants use sunlight and carbon dioxide and water to spin sugar out of thin air. They’re the only thing on Earth that can do that, make pure glucose energy out of thin air. As such, every molecule of sugar that has ever passed through our bodies was first woven by a plant. We’re all just recyclers. And of course, our brains are organs that run chiefly on glucose, this plant-sugar. Without it our thoughts but also our lives more generally would cease. Our thinking about plants in this moment is made possible by plants. 

Every molecule of sugar that has ever passed through our bodies was first woven by a plant. Our brains are organs that run chiefly on glucose, this plant sugar. Without it our thoughts but also our lives more generally would cease. Our thinking about plants in this moment is made possible by plants. 

Plants are also geniuses at synthesising chemical compounds. Some of those compounds we know influence the behavior of animals; these are called “semiochemicals.” Some plants are able to summon beneficial predators to eat whatever’s eating them, or repel grazers, or induce a bee to visit them. Plenty of people have suggested we don’t know the full scope of those compounds’ influence on us. We may be more influenced by plants’ semiochemicals than we realize. I find that thought unsettling but in a delightful way. We are influencing them, by way of agriculture and managed breeding and whatnot. But they are also influencing us.

JJL: That’s such a beautiful circularity! Yet you also seem to point to how language then distances us from plants?

ZS: There is a lot of anxiety in the sciences about anthropomorphization. Plant scientists, I think reasonably, don’t want to cast plants as little humans. Plants have worlds of senses we can’t even really imagine; they do things we cannot, and their branch of life diverged from ours a very long time ago. We are in some ways aliens to each other. But I also think this anxiety about using human-legible language to talk about plants robs the general public of coming to grips with the ways our lives are in fact very parallel. I don’t think it’s a stretch to say a plant can feel one’s touch—we know plants respond to touch, we can watch it in their bodies, how they activate their immune systems to deal with physical threats, how they’ll change their growth pattern if you pet them. There’s a sort of risk in using human language, that things will get too simplified, too untrue to what plants are. But I think it’s a worthwhile risk. We have to deal with that ambiguity of otherness and similarity and hold both in our minds at once. 

JJL: You write about a moment in the scientist Simon Gilroy’s lab, where the plant lights up in response to your touch. How did that change you?

ZS: Oh, it changed me instantly. You’re talking about an experiment where a modified plant imbued with fluorescent green proteins actually lit up in response to me pinching it with tweezers. I had been researching plant behavior and plant…alacrity, I guess you could say, for several years at that point. But I was struggling to connect the things I was learning to actual plants in front of me. This is the trouble: They react in ways either too slow or too invisible—as with chemical changes—for us to see. But then all of a sudden, I watched a plant react to my pinch in real time. Something clicked for me: Here was a very responsive creature. Any lingering doubts I had, and the whole intangibility of plant sensing, went out the window for me in that moment. It became very present. You can’t unsee it! 

I imagine you’ve had a similar turning point. Did this process of contemplating the plants in your life change your relationship to them? Do you see them differently now?

JJL: I think the big thing I noticed working on the book was that, somehow in tracing the biographies of these plants, it was like giving them space to show me who they were. It was an act of cultivating wonder, really. And now I find that the fullness of their lives—what brought some bok choy to my kitchen, what brought citrus to my table—is something that now attaches itself to how I greet these plants daily. I think it made my relationship less instrumental, more respectful. I take a quiet awe in their journeys.

ZS: That’s beautiful. Exactly, it’s a thing you can’t unsee. In thinking about how an ethics of plants might arise, it does feel like a one-way thing: The circle of regard widens, it doesn’t go the other way. Even with weeds! The most disrespected plants. Invasive species-type-weeds specifically. You write beautifully about weeds and the places they hold in our minds, how we come uncomfortably close to notions of nativism and purity when we talk about them. They tell us something about our human anxieties. When I was reading about the giant hogweeds so reviled in the United Kingdom, I was thinking about the Japanese knotweed that is often portrayed as a menace where I am, in New York. It takes over empty lots and I understand it can get into the foundations of buildings, exploiting cracks and widening fissures. Of course, from the plants’ perspective, they’re just doing an excellent job at being plants, finding ways to thrive where we’ve put them, even if that’s far from where they originally evolved to live. What do you make of our human anxieties about weeds?

Revisit Jessica’s thoughts on the most dangerous plant in Britian here.

JJL: I was SO scared to write that chapter of the book, unpacking invasion ecologies, because people get really riled up about invasive species. But I knew that if I wanted to write the book I was writing, it needed unpacking. I wanted to do my homework to really understand the terminology myself. And in writing it, I started thinking a lot about shifting contexts, like how at certain times certain species hold our attention in different ways: giant hogweed being a valued garden plant, until suddenly it isn’t anymore. And how that’s not the only shift taking place: that because of anthropogenic climate change, that species has to move again because winters in the place where it is “invasive” are not really cold enough for it anymore! It just really underscored how our value systems are liable to change. And of course, really drove home for me that resonance with how we discuss people: immigrants as good if they are “good immigrants”, model minorities, as abhorrent if they don’t fit into a desired frame. 

When you write about invasion ecology in your book, you tie it to the idea of agency. I wonder what you make of this: the idea of plants having agency, and how that may differ from our conventional understandings of the term. I saw you refer to Jane Bennett a lot, for example. What’s your take?

ZS: Absolutely. Intelligence and consciousness are loaded terms. I am very interested in them, but it is still unclear if we’ll ever slough off our human-centric academic notions of them. “Agency” is more available for thinking about plants, and perhaps more precise. It gets at the idea that plants are not passive recipients of the world. They take into account their surroundings, the conditions, and shape themselves accordingly. The environment is working on them, and they are working on themselves in response. Their lives have direction, and it’s a direction of their making. That’s what agency—biological agency—here means: purposeful active determination of one’s life. Jane Bennett talks about “vibrancy” being a useful classification—that lots of things in our lives have their own vibrancy, a livingness that sparkles with a kind of internal force. You don’t have to talk about consciousness to talk about vibrancy. Plants have that. When I look at the Japanese knotweed poking up hard beaks of new shoots in an empty lot near my apartment—this is happening right now, because it’s April—I see a deep will toward life, an agentive push to absolutely destroy a tarp someone set out to try to suppress them. They’re solving their lives’ problems and absolutely finding a way. That’s agency.

The word “agency” gets at the idea that plants are not passive recipients of the world. They take into account their surroundings, the conditions, and shape themselves accordingly.

JJL: I love this idea. It has me thinking about how much your book is a kind of portrait of how science changes its mind. Or sometimes doesn’t!

ZS: Definitely. The orientation of science toward plants (and lots of other nonhuman creatures) has shifted so much over the last 150 years. We of course all suffer from a sort of shifting baseline syndrome where the science of our day feels as though it was always true, a sort of natural truth. But a century ago medicine was very sure that dogs, for example, had no capacity for sensation, and so could not feel pain, leading to a lot of gruesome anatomy demonstrations on live animals. That of course now seems nuts. But that too was science! It’s a reminder that ethics and philosophical considerations are often what intervenes in science when it comes to living creatures. Vivisection didn’t stop because science changed its mind but because animal welfare societies picketed them enough. The culture shifted. That’s sometimes what changes the direction of scientific thought. 

I do think we’re on the precipice of a cultural shift around plants—scientists themselves simply can’t unsee the things they’re learning now about what plants can do. Once that collides with the public’s sense of ethics, there will be no going back. I was struck in your book when you were writing about tea, it was such a reminder about how slippery certain sciences are, in that case with regard to taxonomy. It took European science a really long time to realize black and green tea were the same plant, right? 

JJL: Yes exactly! And this really brings into the open the fact that science isn’t in a bubble. That the reason tea was mistaxonomized (is that a word?) was because the social and cultural knowledge that went with tea plants was not available to Europeans when the plant was “named” by Linnaeus: anyone with up-close knowledge of tea cultures in China, for example, would’ve known it was just about how the plant was processed. Science really needed that other cultural piece to get it right. And of course, that resulted in its own problematic and now-famous history of the British stealing not just plants but knowledge too.

ZS: Mistaxonomized should be a word, if it’s not. 

JJL: Speaking of taxonomy, there is a moment in your book where you’re actually in Berlin, where I live, at the botanical garden. And you write about this plant, Nasa poissoniana—which you call a memory plant. What is the significance, do you think, of this idea of plants having memory? I’m struck that memory really links to this idea of plants and history and time unfolding, a kind of cultural embeddedness, to put it ineloquently.

Even the memory of a plant helps me feel like I have some kind of community to belong to.

ZS: No, that’s very eloquent. Yes, that flower is the first, I believe, to be found to take note of time intervals between visits from its pollinator, and parcel out its pollen accordingly. There’s a clear evolutionary utility to that: I was watching that flower do its thing in a German garden, but its home is at high altitude in the Andes, and sometimes there are very few pollinator insects flying around. They have to make sure every visit counts. They take note of the last time interval between visits, and present their pollen when they expect the next bee to arrive. It looks like they’re predicting the future, but it’s actually memory at work. Plants are living libraries of their own lives in more basic ways: Their body structure is a map of where water and sunlight was at different times in its life. Now when I see a bare branch on a side of a tree, that’s a memory of where sunlight once fell, where it was once worthwhile for that plant to grow leaves to catch light. Eventually it got shaded out, and the plant switched efforts elsewhere, to a different branch. Plants record time passing in their body, the elapsed periods of cold and warmth and struggle, like drought, is all there, changing their approach to the world. It brings them closer to us: Our memories are also written in our bodies. I think of epigenetics, the emerging field of medicine that recognizes how generational memories are also inscribed in us. Generations of plants have this too, their parents’ environment changes how they’ll respond to the world too. We are all shaped by place. That’s what your book really gets at: Placedness and how that arranges new possibilities for growth. 

You moved over and over during the time you wrote this book. You were pregnant, then had your daughter. You were uprooted from your home in the U.K. because of rising housing costs, and had to start life again in Germany. It felt like you were in transition on almost every page, even when you were describing your childhood, moving between the two cultures of the sides of your family and also between their houses. How have plants moved with you, and how have your plant-worlds changed? What plants have remained the most consistent? 

JJL: I love this question, and that it follows on you mentioning epigenetics. Because when I was pregnant was the first time I learned about that, probably from TikTok or something, and I have been haunted by that thought ever since. And really in a way, it’s like every move I’ve made in my life, I’ve been haunted by past places and past plants. I think writing the book, really pulling at the threads of why a specific mango tree meant so much to my childhood, and why my mother had her own mango connections, and why soybeans signified such important things to me, it kind of drove home this idea that we make families, communities really, not just from human connections. That plants—especially those we eat or cultivate or have this kind of domestic, intimate closeness with—are kin. So even though I keep moving, and the book traces just a fraction of the moves I’ve made in my life, I carry those connections with me. Even the memory of a plant helps me feel like I have some kind of community to belong to. 

ZS: That’s beautiful. They make us and we make them.