Schlanger, exhausted and emotionally detached from climate reporting, turns to plants to rediscover wonder.

Schlanger walks through the Hoh Rain Forest and is humbled by its complex, interconnected ecology.

During lunch breaks, Schlanger reads about Azolla filiculoides, the world's smallest fern, and becomes obsessed.

Schlanger quits her journalism job to devote herself fully to researching plant intelligence.

Zoologist David Rhoades-Davey publishes research showing that trees changed their chemistry to kill invading caterpillars.

Rhoades-Davey discovers that trees far from the caterpillar infestation also changed their chemical composition.

The Mimosa pudica plant folds its leaves inward when a human finger runs along its stem.

Schlanger visits Simon Gilroy's lab and watches plants respond to a touch stimulus with a ripple of bioluminescence.

Researchers Cocroft and Appel discover that plants release chemical defenses when exposed to predator sounds alone.

Researcher Tilo Henning discovers that the plant Nasa poissoniana appears to have memory and can count time intervals.

Ecologist Consuelo de Moraes discovers that bumblebee bites cause a plant to flower up to 30 days ahead of schedule.

Schlanger travels to Chile and witnesses Boquila trifoliata mimicking the leaves of surrounding plants firsthand.

Evolutionary ecologist Susan Dudley discovers that searocket plants leave room for relatives but crowd out unrelated neighbors.

Schlanger visits researcher Tony Trewavas in Edinburgh, who declares that humanity has already passed the point of no return.

Schlanger argues that embracing collective, ecological thinking could still shift humanity's destructive relationship with the planet.

Burned out and emotionally detached from years of climate reporting, Schlanger turns to plants to recover her sense of wonder, eventually quitting her journalism job to pursue plant science full-time. Her investigations take her from researchers who prove trees chemically warn one another of predators to a lab in Wisconsin where she watches plants glow in response to touch. She uncovers evidence that plants can respond to sound, hold something like memory, and manipulate insects into becoming unwilling partners. Traveling to Chile, she witnesses a vine that shapeshifts to mimic surrounding plants, and at home she meets researchers who show that plants share resources preferentially with their genetic relatives. Each discovery deepens her argument that plant life is far more dynamic and intelligent than Western science has acknowledged. The journey ends with Schlanger choosing hope over a researcher's pessimism, proposing that a collective, ecological way of thinking could still change humanity's relationship with the planet.

Schlanger's personal journey from climate burnout to plant advocate.

Schlanger reads Oliver Sacks's Oaxaca Journal and recognizes a recurring naturalist feeling of being at one with the natural world.

Schlanger enrolls in a ferns class and learns that ferns chemically sabotage the sperm of competing fern species.

The 1973 book The Secret Life of Plants, built on dubious research, creates lasting stigma that discourages study of plant behavior.

Darwin observes that root tips maneuver around obstacles toward nutrients, comparing the process to cognition, but his contemporaries disagree.

Hawaii's Plant Extinction Prevention Program illustrates how isolated island plants flourished until climate change and human activity threatened them.

Aristotle establishes the ladder of life, placing humans at the top and positioning plants on the lowest rung.

Theophrastus, left to run Aristotle's school, publishes early works treating plants as a distinct category rather than a lesser one.

Scientists discover that trees can detect cicada eggs laid on their limbs and encase them in a suffocating woody callus.

Venus flytraps are found to use electrical bursts in their hairs to count the number of times prey touches them.

A long-tongued bat in Cuba relies on a flower's specialized echo-amplifying appendage to locate nectar via echolocation.

Monica Gagliano's maze experiments reveal that plant roots navigate toward the vibration of water flowing through sealed pipes.

Nasa poissoniana dilutes its nectar to force pollinators into making multiple visits, spreading its pollen more widely.

The plant bittersweet nightshade emits sugary nectar to lure ants, which then protect it by eliminating flea beetle larvae.

The plant Spigelia genuflexa bends its own stem to bury seeds in soft moss where its offspring have the best survival odds.

Trewavas argues that scientists too often hyperspecialize on isolated data points rather than embracing a broader systems-based view.

The study of plant intelligence carries a long and complicated history, beginning with Aristotle's hierarchical ladder of life and the alternative vision of his successor Theophrastus, who saw plants as distinct rather than lesser. A wave of discredited science in the 1970s created a stigma that stifled research for decades, but compelling discoveries kept emerging, from trees trapping cicada eggs in woody calluses to Venus flytraps counting the touches of their prey. Researchers revealed that plants engage in complex interspecies relationships, recruiting ants as bodyguards, exploiting bats through acoustic architecture, and directing root growth toward the sound of flowing water. Evidence of plant parenthood, including one species that bends its own body to place seeds in optimal soil, challenged the boundary between instinct and care. A landmark study showing that diet can fully override a genetic predisposition to cancer then reframed what it means for any organism to have an individual destiny. The section closes with a leading researcher arguing that the way science is practiced — hyperfocused on isolated details — mirrors the very blindness Schlanger has spent the book trying to correct.

The scientific history and key discoveries that underpin plant intelligence.

Schlanger spots the invasive tree of heaven growing defiantly at her New York City doorstep, igniting her curiosity about plants.

Schlanger learns that words like 'intelligence' and 'consciousness' are so polarizing they instantly end conversations with plant researchers.

A group of scientists at Cambridge University formally declares that all mammals and birds possess consciousness.

Botanists explain that widespread plant blindness in Western culture makes it extremely difficult to secure funding for botanical research.

Researcher Van Volkenburgh discovers that plant cell membranes contain ion channels regulating electrical flow, mirroring animal cell behavior.

President Clinton uses his State of the Union address to announce cuts to federal funding for plant stress research.

Appel and Cocroft, suspicious of their own findings, scrutinize every detail of their experiments and find their results confirmed.

Flowers are discovered to increase the sweetness of their nectar in direct response to the vibration of a nearby bee's buzz.

Desert plants are found to prepare their cells to absorb water specifically in response to the sound of thunder.

Nasa poissoniana is found to anticipate a pollinator's return and release its pollen-laden stamen moments before the insect arrives.

Ernesto Gianoli finds that Boquila trifoliata has mimicked an invasive plant species that has only existed in the region for under ten years.

Schlanger personally witnesses Boquila trifoliata imitating a fern, a behavior no scientist had ever previously documented.

Sunflower farmers in Argentina discover that planting genetically related plants together significantly increases crop yields compared to unrelated pairings.

Researchers find that plants experiencing stress make poor root-foraging decisions, a parallel to how human stress impairs cognition.

Trewavas tells Schlanger that humans are simply not wired to perceive or feel the complex systems in which they live.

From the moment Schlanger notices an invasive tree thriving defiantly at her New York City doorstep, she begins to question what science has overlooked about plant life. She quickly discovers that the scientific community is deeply divided, with certain vocabulary capable of ending research conversations instantly, even as declarations from Cambridge signal that the field is ready to evolve. Landmark experiments reveal that plants generate electrical signals akin to nervous systems, respond directly to sound, and time their own biology to match the rhythms of their pollinators. A vine in Chile pushes the question further still: if it can mimic a plant that arrived in the region less than a decade ago, something far faster than traditional genetics can explain must be driving the change. Evidence that related plants share resources preferentially and that stressed plants make poor decisions mirrors human cognitive experience in unsettling ways. The book closes with a sobering admission that the complex systems governing life on Earth exceed human intuition — but Schlanger implies that recognizing this limitation may itself be the first step toward a wiser relationship with the living world.

The key revelations and turning points that reshape understanding of plant life.