In 1973, journalist Peter Tompkins and former CIA operative Christopher Bird introduced a radical new idea to the world: plants, they said, can hear. And not only that, but they also love music. In their book, The Secret Life of Plants, Tompkins and Bird cited a slew of reports that backed up these remarkable claims—including stories of Charles Darwin’s bassoon performances for his Mimosa pudica and cases where plants had grown toward radios playing classical music. (Rock, they claimed, stunted the growth of others.)

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Almost overnight, The Secret Life of Plants changed the way much of the public saw the trees and flowers around them. According to the authors’ seemingly authoritative research, plants were “living, breathing, communicating creatures” that could respond to human touch, thought, and emotion. The book then went quite a bit further, arguing that plants were “endowed with personality and the attributes of the soul.” In other words, people and plants may not be so different after all.

Tompkins and Bird’s book had arrived at an opportune time to hit the mainstream. The early 1970s saw mounting public concerns around pollution and the protection of the environment—worries that were reflected in the formation of new governmental bodies, like Environment Canada in 1971. The same year that The Secret Life of Plants was released, Dorothy L. Retallack’s The Sound of Music and Plants and Shirley Ross’s Plant Consciousness, Plant Care also hit bookshelves, backing up the idea that plants may be more “human” than previously thought. Many in the public ate up this idea, and the resulting sales pushed The Secret Life of Plants onto the New York Times Best Seller list.

The success of the book even spawned a cottage industry of musicians writing and releasing music with plants as the intended audience. Albums included Green Sounds (Music For Your Plants) as well as works from French composers Roger Roger (De la musique et des secrets pour enchanter vos plantes) and Joël Fajerman (L’Aventure des plantes). But the most culturally significant album may have been Mort Garson’s 1976 Plantasia. The synth-heavy record focused on specific types of flora track by track, from Chlorophytum comosum (spider plant) to Sansevieria trifasciata (snake plant). And, while it’s hard to look at song titles like “Rhapsody in Green” and “You Don’t Have to Walk a Begonia” and believe that Garson was writing the album completely straight-faced, his humour never feels trivializing of the material or concept.

Within a few short years, The Secret Life of Plants played a part in transforming Western culture’s understanding of plant life, feeding into an escalating thirst for knowledge about the leafy friends who live among us. There was just one problem: much of the book was rubbish. And scientists soon made their frustration with the book’s popularity clear, releasing article after article discrediting its purported research and results. Tompkins and Bird may have seen financial success, but they also inadvertently set back the field of plant science they had aimed to advance, making a laughing stock out of anyone properly researching the relationship between plants and sound.

Now, some forty years on, scientists around the world are risking their reputations by taking another look at how plants interact with sound. And, though these researchers don’t dispute the idea that pop-science books like The Secret Life of Plants were full of pseudoscience, they do say the underlying idea that plants can “hear” may have some veracity after all.

Throughout history, people have chosen to decorate the interiors of their homes with ficuses, ferns, and African violets. In earlier centuries, greenhouses allowed the rich and well-travelled to keep citrus plants and other exotic varieties alive in colder climates. And, as indoor heating became more efficient, homeowners in Victorian-era England brought more and more plants into their immaculate parlours. Each surge in plant popularity has been driven by science as much as by fashion.

The tropical houseplant boom of the 1970s, for example, arrived alongside new improvements in shipping infrastructure. Jill Jensen, a third-generation horticulturalist, says that, in the 1950s, her family business in Newcastle, Ontario, discovered that it was cheaper and easier to build a greenhouse in Apopka, Florida, and have the plants shipped to Canada. With new access to a world of once distant tropical plants, some green-thumbed readers in the 1970s latched on to Tompkins and Bird’s idea that there may be more happening within a leaf than previously imagined.

But the media and academic communities were not as easily swayed, and both pounced on The Secret Life of Plants’s many glaring leaps in logic. Take the chapter “The Harmonic Life of Plants”: Tompkins and Bird daisy-chain concepts drawn from disparate sources, jumping from esoteric texts that claim everything in the universe has a spirit, to research from American chemist Donald Hatch Andrews that hypothesizes all matter is music since all matter in the universe vibrates, to the work of a German thinker who posits that the lines on a leaf are spaced apart like octaves. “From Tompkins and Bird, you’d never know what, let alone whom, to trust. They try to coat everyone equally with respectability and plausibility,” wrote Elsa First in the New York Times. “Unexplained phenomena lend themselves to a lot of anthropomorphizing and the naive postulation of all kinds of ‘rays’ and ‘energy fields’ which sound every bit like psychotic fantasy.” In the April 1974 issue of the journal BioScience, plant physiologist Frank B. Salisbury wrote a letter questioning the lack of repeatability, proper controls, and objective observations of the book’s experiments, and labelled the end result “pseudoscience” and “superstition.”

All of this critical pushback had an effect on others who were working within the wider field of plant research. One scientist, speaking under the condition of anonymity to the Globe and Mail in 1978, said his experiments on the effects of sound on plants had made him a target of ridicule. “I got the reputation of being a nut. I want to forget the whole blinking business. I don’t want my name associated with any of this. For one thing, it’s murder when I apply for grants for other research, and you can’t do research without grants.”

It’s difficult to say how many other researchers dropped the subject due to the popularity (and critical dismissal) of The Secret Life of Plants. Those who have stuck with plant-cognition studies have been slowly picking up the pieces ever since. “From a scientific perspective, and as a scientist myself, [the book] has caused me a lot of grief,” says Monica Gagliano, a professor at the University of Sydney. “It has, in a way, frozen the entire field because no respectable scientist would ever touch this kind of topic,” she says.

In her 2018 book, Thus Spoke the Plant, Gagliano recounts how, in studying the ways plant behaviour and morphology all respond to sound as a stimulus, she’s faced a tremendous amount of adversity from granting bodies, fellow faculty, and the scientific community at large. “The research officer said, ‘Monica, that is career suicide!’ in response to my decision to write a proposal on understanding sound communication in plants for the upcoming round of grant applications from the Australian Research Council,” she details in her book. Later, she recounts how a fellow colleague responded to her proposal with a sneering “Is this a joke? That is not science!” while others chose to just ignore her work outright. Like The Secret Life Of Plants, Gagliano’s book disturbs the presumed distance science has from personal narrative. But, in her case, the studies she cites are actually verifiable.

In Thus Spoke the Plant, Gagliano summarizes her 2017 study in which the roots of pea plants were exposed to the recorded sound of water with no detectable moisture gradient in their soil. To her surprise, the seedlings extended their roots in the direction the sounds were coming from. As scientific method demands, these experiments were designed to be repeatable, and Gagliano is slowly finding that other researchers are following suit. A team of scientists at Tel Aviv University recently published the results of a peer-reviewed study that demonstrated plants were rapidly responding to the sounds of pollinators: the concentration of sugar in the flowers’ nectar increased as they were exposed to the recorded sound of bee wingbeats. Gagliano says scientists always knew there was a relationship between bees and flowers, but this research shows how sound is being used as a medium for meaning—and suggests a level of intelligence in plants we have yet to understand.

One would think that Gagliano would be nothing but critical of The Secret Life Of Plants, but she has a rather generous way of looking at it: “The fact [is] that people have this desire and this need to know that these plants are alive and there is a possibility to exchange something,” she says. “I think that that’s what [the book] has instilled—a passion that is still alive and, in a way, is the same passion that is still driving the science.”

Gagliano points to a more recent book, Peter Wohlleben’s The Hidden Life of Trees, to show how the issue of shoddy pop science still endures. Wohlleben’s book has similarities to The Secret Life of Plants in more than just name: he also largely paraphrases scientific studies to come to his conclusions, and, Gagliano says, he misrepresents some of her work. “Again, it’s misleading the public, it’s not telling the real story, the science is not correct. It’s all of those things,” she says. “But, from a cultural perspective, look what he’s done. It’s being published everywhere in, I don’t know, fifty languages, and there is a new awareness about this work.”

This increasing awareness around plants is evident in other ways too. Mort Garsons’s 1976 album, Plantasia, was reissued last summer by the New York label Sacred Bones Records, and there is even an upcoming documentary about Garson now in early development. In addition, the sale of houseplants is once again reaching heights that mirror those of the 1970s, thanks to a “regreening” of the home and commercial spaces. Horticulturalist Jensen says that “there’s sort of a one-upmanship” happening on social media, where plant influencers are sharing pictures of their homes that include some rare plant varietals. Previous trends in houseplants were driven by homeowners in their forties, fifties, and sixties, but this time, Jensen says, millennials living in small condos and rental units are the primary motivators.

Though the research into plant cognition is once again achieving legitimacy within the scientific community, don’t expect there to be any major findings on which albums will help your plants grow better any time soon. “The truth is that music is a very human thing,” Gagliano says. “So, from an evolutionary perspective, who cares? Why would plants care about it?” Though, before completely shutting down the idea, she hesitates: “Yet, they have lived with us, in our houses and in our apartments, for a long time now, so maybe they do care.” For her, the key to learning more about plant cognition is not rushing the research. “What the Indigenous of many cultures, if not all cultures, have done for millennia is to build these relationships with plants over time,” she says. And, once the relationship is on solid ground, plants are more than happy to share their secrets.

Michael Rancic Michael Rancic is a Toronto-based freelance journalist whose work has appeared in Now Magazine, Bandcamp Daily, Spacing, and Musicworks Magazine.