Does Anyone Actually Know What A Plant Is?

As author Zoë Schlanger dives into the world of plants, she finds it’s filled with contradictions, mysteries, and astonishing ingenuity.

The following is an excerpt from The Light Eaters: How The Unseen World Of Plant Intelligence Offers A New Understanding Of Life On Earth by Zoë Schlanger.

When you purchase products through the link on this page, Science Friday earns a small commission which helps support our journalism.

The light eaters book cover

Buy the Book

The Light Eaters: How The Unseen World Of Plant Intelligence Offers A New Understanding Of Life On Earth


I am walking along a dim path. Thick hillocks of moss undulate fuzzily around me. I look up, and am dwarfed by pillars of dank and slimy wood. The earth below me is damp, has give. A sign on the path tells me to be alert for aggressive elk in the area. I see no elk, I keep walking. Plumes emerge, sword ferns with their curled fiddleheads the size of a baby’s fist covered in velvety auburn hair, the unexpected prequel to the arching fronds that will fountain out above them like peacock feathers. Moss drips in long fingers from branches overhead. Fungi arc skyward from a downed tree. Everything seems to strain upward and downward and outward at once.

I intrude on all this, but no one notices. All things here are so thoroughly absorbed into their own living that I am like an ant slipping discreetly through a sponge. The lichens crawling up the base of trees curl the edges of their disklike bodies up, catching drops as they receive a new day and another chance to grow.

I am in the Hoh Rain Forest in the Pacific Northwest, and everywhere is a sense of secrets. And for good reason. For everything that science does know about what, biologically, is going on here, there is so much more it cannot yet explain. All around me are complex adaptive systems. Each creature is folded into layers of interrelationship with surrounding creatures that cascade from the largest to the smallest scale. The plants with the soil, the soil with its microbes, the microbes with the plants, the plants with the fungi, the fungi with the soil. The plants with the animals that graze on them and pollinate them. The plants with each other. The whole beautiful mess defies categorization.

Thinking about this, I am reminded of the concepts of yang and yin, the philosophy of opposing forces. We know that the forces that shape life are in constant flux. The moth that pollinates the flower of a plant is the same species that devours the plants’ leaves when it is still a caterpillar. It is not, then, in the plant’s interest to completely destroy the grazing caterpillars that will metamorphose into the very creatures it relies on to spread its pollen. But likewise the plant cannot bear total leaf destruction; without leaves, the plant can’t eat light, and it will die. So after a while the besieged plant, having already lost some limbs and therefore showing tremendous restraint, judiciously begins to fill its leaves with unappetizing chemicals. At least most of the caterpillars will have eaten enough to survive, metamorphose, pollinate. Everyone in this situation comes within a hair of death to ultimately flourish. This is the push and pull of interdependence and competition. At the grand scale, no one seems to have yet won. All parties are still here, animals, plants, fungi, bacteria. What we end up with is a sort of balance in constant motion. All of this pushing and pulling and coalescing, as I have come to understand, is a sign of tremendous biological creativity.

How to get our minds around all of that complexity is the shared professional problem of science and philosophy, but also of every person who’s stopped to wonder. All that roiling life that won’t stand still long enough for us to get a good look. Narrowing our focus to only plants seems at first sensical; that should be easier, being one thing. But that quickly proves naive. Complexity lives at every scale.

Journalists in my line of work tend to be focused on death. Or the harbingers of it: disease, disaster, decline. That is how climate journalists mark time as the earth passes benchmark after grim benchmark on its way into the foreseen crisis. There is only so much of this that one person can take. Or perhaps my tolerance was thin and easily worn out after years of focus on droughts and floods. In recent years I’d begun to feel numb and empty. I needed some of the opposite. What, I wondered, is the opposite of death? Creation, perhaps. A sense of becomings instead of endings. Plants are that, given as they are to continuous growth. They’d soothed me all my life, long before studies came out confirming what we already knew: that time spent among plants can ease the mind better than a long sleep. Living in a dense city, I’d walked in the park under a canopy of yews and elms when I needed to clear my head; I’d spent long minutes gazing at the new leaves forming on my potted philodendrons when my nerves were fried. Plants are the very definition of creative becoming: they are in constant motion, albeit slow motion, probing the air and soil in a relentless quest for a livable future.
Related Segment

The Unseen World Of Plant Intelligence

In the city, they seemed to make a home in the least suitable places. They burst from cracks in crumbling pavement. They climbed the chain link fence at the edges of garbage- strewn lots. I privately delighted as I watched a tree of heaven— loathed as an invasive species in the Northeast— emerge out of a split on my stoop and grow nearly to the size of a two- story building in a single season. Privately, because I knew this was seen as a hellish species in New York, in part because it injects poisons into the ground around its roots to prevent anything else from growing nearby, thereby securing its patch of sun; delighted, because this seems devilishly brilliant. When my neighbor cut the tree down with a machete late in the season, I understood. Still, I regarded its stump with admiration on my way out of the house every morning. It was already sprouting new green protrusions. You have to respect a good hustle.

So plants seemed like the right place to land my weary apocalyptic attention. Surely they would refresh me. But I soon learned they would do more than that. Plants have, over the course of years of obsession, transformed my understanding of what life means, and what its possibilities are. Now as I gaze around the Hoh Rain Forest I see more than a soothing wash of green. I see a masterclass in living to one’s fullest, weirdest, most resourceful potential.

To start with, a life spent constantly growing yet rooted in a single spot comes with tremendous challenges. To meet them, plants have come up with some of the most creative methods for surviving of any living thing, us included. Many are so ingenious that they seem nearly impossible for an order of life we’ve mostly relegated to the margins of our own lives, the decoration that frames the theatrics of being an animal. Yet there they are all the same, these unbelievable abilities of plants, defying our anemic expectations. Their way of life is so astonishing, I will soon learn, that no one yet really knows the limits of what a plant can do. In fact, it seemed that no one quite knows what a plant really is.

This is of course a problem for the scientific field of botany. Or it’s the most exciting thing to happen to it in a generation, depending on how comfortable you feel with seismic shifts in what you once thought to be true. Now I was hopelessly intrigued. Controversy in a scientific field tends to be a harbinger of something new, some new understanding of its subject. In this case, the subject was all of green life itself. I began to direct my growing interest entirely toward emerging thought in plant science. The more botanists uncovered the complexity of forms and behaviors of plants, the less the traditional assumptions about plant life seemed to apply. The scientific field was eating itself alive with contradictions, points of contention multiplying as fast as the mysteries. But something in me was attracted to this lack of neat answers, as I suspect many of us are. Who doesn’t feel both drawn to and repulsed by the unknown?

This book will take up these new epiphanies in plant science, and the struggle along the way over how new scientific knowledge is made. Rarely does one get a glimpse of a field in true turmoil, debating the tenets of what it knows, about to birth a new conception of its subject. We will also consider a daring question currently being hotly debated in labs and academic journals: Are plants intelligent? Plants don’t have brains, as far as anyone can tell. But, some posit, they should be considered intelligent regardless, based on the remarkable things they can do. We determine intelligence in ourselves and certain other species through inference— by observing how something behaves, not by looking for some physiological signal. If plants can do things we consider indications of intelligence in animals, this group says, then it’s illogical, a sign of unreasonable zoocentric bias, not to use that language for them. Others go farther, suggesting that plants may be conscious. Consciousness is perhaps the least understood phenomenon in human beings, let alone other organisms. But a brain, this camp says, may be but one way to build a mind.

Other botanists are more circumspect, unwilling to apply what they see as distinctly animal- centric notions to plants. Plants, after all, are their own clade of life, with an evolutionary history that swerved away from our own long ago. Painting them with our concepts of intelligence and consciousness does a disservice to their essential plantness. We’ll meet this camp of scientists too. Yet no one I met— not a single botanist— was anything less than agape with wonder at what they were learning that plants are capable of. Thanks to new technology, scientists in the last two decades have gained incredible new powers of observation.

Their findings are reshaping the meaning of “plant” before our very eyes.

Regardless of what we think of plants, they continue to surge upward, toward the sun. In this ruined global moment, plants offer a window into a verdant way of thinking. For us to truly be part of this world, to be awake to its roiling aliveness, we need to understand plants. They suffuse our atmosphere with the oxygen we breathe, and they quite literally build our bodies out of sugars they spin from sunlight. They made the ingredients that first allowed our lives to blink into existence at all. Yet they are not merely utilitarian supply machines. They have complex, dynamic lives of their own— social lives, sex lives, and a whole suite of subtle sensory appreciations we mostly assume to be only the domain of animals. What’s more, they sense things we can’t even imagine, and occupy a world of information we can’t see. Understanding plants will unlock a new horizon of understanding for humans: that we share our planet with and owe our lives to a form of life cunning in its own right, at once alien and familiar.

In the Hoh Rain Forest, a bigleaf maple stretches out above me. Its trunk is sheathed entirely in licorice ferns and lungwort and spike moss, giving the impression of a tree wearing a Grinch suit. Only a few ridges of the tree’s bark are visible, rising through the green fuzz like a mountain range above a mat of thick woods, like the Olympic peaks that pierce the evergreen forests just east of here. I lean in, looking closer. The green suit is a world within a world, the little tufts and fronds replicating the structure of a forest at tiny scale. Three- leafed oxalis and feathery stairstep moss coat the ground. I am lost in their world, taken into it. Then again, we’ve all been lost in it a long time, unaware of its true machinations. This seems imprudent. I wanted to know, so I went out and looked.

From The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth by Zoë Schlanger. Copyright © 2024 by Zoë Schlanger. Published on May 7, 2024 by Harper, an imprint of HarperCollins Publishers. Excerpted by permission.

Meet the Writer

About Zoë Schlanger

Zoë Schlanger is author of The Light Eaters and a climate change reporter at The Atlantic. She’s based in Brooklyn, New York.

Explore More