Evidence: Plants Are Smarter Than We Think

The other night I was watching a scientific show about the human body. One of the highly educated scientists being interviewed made a comparison that kind of offended me.

I was surprised someone who should be open minded, would say “The only cells in a human, that can think and have memory are brain cells. To say any other cell in our bodies can communicate with thought and memory, is as preposterous as saying plants can think.”Obviously, that scientist doesn’t spend much time around nature as we do in the horticulture industry.

But how would I prove him wrong? First, I got out my Webster dictionary (yes, I still use my dictionary from college) and looked up the definition of “think.” According to Webster, one definition is “to determine, resolve and work out by reasoning.” Another definition is to “intend; to recall, remember.”


Let’s take the definition “to determine.” Plants do have the ability to determine if it’s being harmed. They actually contain their own surveillance system that can respond and defend itself in different ways depending on the situation.

One way a plant does this is by fortifying their cells which is known as the Basal resistance. If that doesn’t work, a plant changes tactics by going into hypersensitive response also known as HR. When a plant goes into the HR response, it starts to kill its infected cells like a partial suicide. This reaction hinders the predator or disease from gaining access to its water supply and nutrients. Like a surgeon, making the decision to amputate a foot with gangrene to prevent the disease from spreading, plants can amputate their own cells to achieve the same results. Plus they can do it without the expensive surgeon.

A scientist may argue that’s just a natural reflex that doesn’t require conscious thought like we do with breathing, but plants also have the ability to distinguish who or what is attacking them and will respond accordingly. This amazing plant defense digests the invader’s genetic material into its memory. The next time that same invader strikes, the plant will respond faster because it has already determined the most effective line of defense. This certainly sounds like a plant has the ability to remember or recall.


aphids on wheat headI know my bare skin can’t come into contact with wet Dieffenbachia leaves; otherwise I break into a rash. What I didn’t know is this is actually another line of plant defense. Some plants can emit toxins that can be deadly to its predators. Other plants can release their own special fragrance as protection. A plant can tell between a small wound or something life threatening such as a hungry insect. In this circumstance, a plant may call out for its own friendly army to attack by releasing chemicals called volatile organic compounds. As an example, if wheat is being attacked by aphids, it will emit its own special volatile scent that signals to cannibalistic aphids that lunch is here. These aphids only eat other aphids and their arrival can save the plant from destruction. As an added bonus, volatile chemicals will warn the nearby wheat plants that danger is near. Wouldn’t you call this a form of communication?


Mimosa pudicaAn experiment was conducted by Dr. Monica Gagliano, a biologist from the University of Western Australia.  Her research suggests that the Mimosa pudica plant is capable of learning from experience. As a defense mechanism, mimosa will collapse its leaves temporarily when disturbed. Gagliano created an apparatus that would drop water onto it causing the leaves the collapse. The contraption dropped water every five to six seconds. After just a few drops, the mimosa plant would stop responding to the stimulus and no longer collapsed its leaves. It learned to tune out the disruption and deemed it irrelevant. The plant was then left undisturbed in a more favorable environment for a month’s time. When the water drops were reintroduced, the learned response to ignore the disturbance remained. Impressive, right?

A gifted botanist named Raoul France believed plants move just like animals and people, except their movement is at a much slower rate. It’s true. Haven’t we all witnessed the plants we install and maintain grow larger and reach toward the brightest source of light? France calls this intent. Intent, being another definition of thinking. A good example of intent is the acacia plant knowing the difference between a good ant and a bad ant. When an acacia plant comes into contact with a bad ant, it will close its leaves protecting its nectar. When beneficial ants rid the plant of the bad ones, the acacia rewards the insects by allowing them access to the nectar. That’s a smart plant in my eyes.

A sixth sense

Would you believe plants not only think, they can also read our minds? It sounds completely preposterous, but Cleve Backster was convinced plants have ESP abilities. He was our country’s top polygrapher in 1966. One day Cleve got a crazy idea while in his office. Realizing his mass cane needed water, he wondered if his polygraph machine could detect the electrolytes moving through the plant. He attached his equipment to one of the leaves and gave it some water. He thought for sure it would record some reaction, but nothing happened. Since the galvanometer can detect emotion in a human, Backster decided to put the leaf in his hot coffee thinking that may create a reaction, but again, it didn’t.

Taking it one step further, he thought about getting a match and severely hurting the leaf by burning it. As he got up to retrieve the matches, the meter started sweeping upwards as to register emotion. It moved even more as he got closer with the flame. The plant was showing emotion. Not wanting to further damage his plant, Backster decided he was going to pretend to burn it again. As he pretended, the needle didn’t move. The only explanation he could think of…is his corn plant understood his thoughts and knew he was faking it. He determined his plant could read his mind.

After that day, Backster became fascinated with plants and conducted many experiments that discovered plant abilities that seem so completely implausible I even have a hard time believing it. I highly recommend reading “The Secret Life of Plants,” about Backer’s experiments as they get more mind-blowing. When I finished reading his book, I had a new appreciation for horticulture. For a while I couldn’t eat a salad without feeling guilty. Plants have been on this earth millions of years longer than we have. They just might know a lot more than we do.

As I learn more about the mysterious plant world, I like to share some of these ideas with my clients. Like myself, they look at the plant sitting on their desk in a whole different light. So whenever someone sees me working and asks, “Do you talk to your plants?’

I reply, “I don’t have to talk to them, because they already know what’s on my mind.”


If you find this topic interesting and have an hour to kill, check out this great documentary titled “What Plants Talk About” by experimental plant ecologist, JC Cahill.



“New research on plant intelligence may forever change how you think about plants”. PRI
Featured image by StoneFace Creations
“Aphids on wheat head” photo by MUExtension417
“Mimosa pudica” photo by BlueRidgeKitties

Sherry has been part of the interiorscape industry for over fifteen years, starting at an entry level job at North Florida's largest greenhouse and currently owning two horticulture companies. At UMaine, Sherry majored in English where she worked part-time writing scripts for a local college TV studio.

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