Written by: Di Graski, Colorado Master Gardener Apprentice, 2024
In 2018, Zoë Schlanger knew she needed help: after years of reporting chronically bad environmental news for Newsweek and then Quartz in the mid-Twenty-Teens, she had become inured to the point of numbness, emptiness. She turned to plants: a New York Botanical Gardens course on ferns was her first lifeline. Thus began Ms. Schlanger’s six-year journey through recent botany breakthroughs, culminating in the publication of her first book, The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth (HarperCollins, May 2024).
I heard National Public Radio’s Fresh Air interview of Ms. Schlanger at the beginning of May and immediately knew I wanted to read her book. I enjoy reading about Science. CSU Extension’s dedication to Science is what drew me to the Master Gardener program: Extension’s enabling legislation charges it with the “dissemination of information to the people of this state in order to assist them in applying the results of scientific research and technological developments.” Carl Sagan and Isaac Asimov’s science fiction are among my favorite reads, and I’ve gobbled up recent science journalism like Jennifer Ackerman’s bestselling The Genius of Birds (2016) and What an Owl Knows: The New Science of the World’s Most Enigmatic Bird (2023), and Ed Yong’s I Contain Multitudes: The Microbes within Us and a Grander View of Life (2016) and An Immense World: How Animal Senses Reveal the Hidden Realms Around Us (2022).
Like Ed Yong, Zoë Schlanger now works with The Atlantic. If you would enjoy listening to Zoë Schlanger talk about The Light Eaters, you can access NPR’s recordings here, https://www.npr.org/2024/05/06/1249310672/plant-intelligence-the-light-eaters-zoe-schlanger (Fresh Air on May 6, 2024) and here, https://www.sciencefriday.com/episodes/may-31-2024/ (May 31, 2024, Science Friday).
Botanists as early as Theophrastus and Charles Darwin prophesied “plant intelligence” based on their detailed personal observations, but they lacked the technology to collect needed data about plants’ electricity, chemistry, and genetics. The Light Eaters brings its readers plain-English descriptions of awe-inspiring botany, empathetic portraits of the scientists who are performing the research, and the author’s heartfelt pondering about the implications.
Ms. Schlanger predicts that botany is on the cusp of a paradigm shift. Chapter 2, “How Science Changes Its Mind,” refreshes her readers’ understanding of plants’ long history on planet Earth, the philosophy of science, humanity’s historic views of the Plant Kingdom, and the impact of the pseudo-science published in the 1973 bestseller The Secret Life of Plants. The bottom line is that botany has been dominated by a Western view of plants as root-bound automatons, unthinkingly performing biological processes dictated by their genetic material, and nothing more. Any scientific investigation into “plant intelligence” – plant communication and relationships with other plants, fungi, bacteria, and insects; plant decision-making and agency; plant senses and memory – is dismissed as rank anthropomorphizing.
But the rest of The Light Eaters presents compelling research findings that cannot be reconciled with plants as passive automatons. Recent experiments reveal plants as incredibly sensitive creatures: able to perceive light waves beyond humans’ ken; able to sense chemical signals from neighboring plants and invading insects; able to hear running water and gnawing caterpillars. Even more to the point of “plant intelligence,” botanists are finding that plants understand their neighbors’ senses (what we humans call sight, smell, and hearing) and engage in purposeful – and effective – communication with them. One example is plants’ discernment of the types of caterpillars eating their leaves from the chemistry of the caterpillars’ saliva, followed by the plants’ concocting and emitting the perfect chemical message to summon those caterpillars’ predators, such as parasitic wasps.
Of course, “plant intelligence” deniers demand an explanation of how a being without eyes, ears, or brain could possibly be said to see, hear, and decide. Botanists honestly answer, “We don’t know yet,” but also point to paradigm-busting research showing that plants use electricity to communicate near-real-time data about their environment to their whole beings and that pea sprouts’ roots consistently choose a path toward water, even if their only clue is sound. Chapter 8, “The Scientist and the Chameleon Vine,” is an in-depth report of current research into the mimicry-mastering, Chilean vine Boquila trifoliolata . . . and it will blow your mind. Speaking of human minds, plant neuroscientists point out that our brains do not have a “central processor,” either: human consciousness seems to be the product of a network of brain regions, without a single command post.
The driving force of plants’ evolution of such amazing capabilities is, of course, survival. But The Light Eaters makes clear that this is not an “every plant for itself” concept of survival; instead, scientific research indicates that plants engage in altruistic behaviors, especially toward their children and kin.
Ultimately, Zoë Schlanger’s new-found understanding of plants proved to be a balm for her pessimism, an antidote for numbness:
If I’ve learned anything, it’s that biotic creativity is our inheritance. Rather than seeing a march toward doom, as I did as a disaffected office worker writing the news, I now see a boundless sea of change. Life finds a way, if given a chance.
I recommend The Light Eaters to my fellow gardeners. It will help all of us better recognize and appreciate feats of plant intelligence in our own gardens and neighborhoods, and, as the author shares, “open[] up a chance to remodel the way we see the nonhuman world, and our place in it.” Now when I witness my pea plants sending their tendrils toward solid supports that will withstand even Pueblo County’s relentless winds, I am awed by a creature manifesting its intelligence and its will to thrive.