Scientists have known for decades that plants talk to each other, but it has always been behind our backs, and, frankly, a lot of your more educated people are not at all confident about how we’re coming off. Less thoughtful folks will think nothing of churning up a swamp with a fat vehicle and a packet of fossil fuel. They are unmoved by botanical trash-talk. But anyone with a heart connected to the biosphere will tend to tread more carefully.

Still, not only do plants gossip, they actively warn each other of trouble on the way. Apparently.

Which strikes me, on the face of it, as just mean. Here are all these plants stuck in the ground and one of them gets nipped by a bug and hollers “Danger! Danger!” and what are all the other plants supposed to do? Just stand around and say “Oh shit?”

Turns out plants can defend themselves against various troubles—being chewed on, being cut, drying out, what have you. And when one is experiencing such trouble, it sends the message out for the rest of them to get ready. It wasn’t known until recently how they do this. Sure, some plants, like strawberries, have runners, but that doesn’t mean they’re galooping across the countryside like Paul Revere. Instead, they release chemical messengers through the air.

It’s called calcium signaling. Plants and people both use ionized calcium to drive processes within their cells. If a mosquito proboscis enters your arm skin and you smack it into a smudge, there’s Ca2+ involved behind the scenes, directing muscles to contract and what-have-you. In a plant, calcium ions might direct the plant to produce toxins. Or they might release compounds into the air to alert nearby birds that they’re under attack by caterpillars (a.k.a. bird snackage).

Sending actionable signals to other plants through the air seems impossible, but I just clicked on the radio in the middle of the Ode to Joy and what blasted into my car from 200 years ago raised all the little hairs on the back of my neck like a waving stand of wheat. They were swaying like a dang chorus. Explain that.

Anyway someone recently modified some plants to make the calcium in them fluoresce, and they were able to see the calcium roaring through the leaves in response to a chemical signal from another plant. This experiment did require them to skoosh another plant and waft its danger fumes around, but this is not considered unethical in the botany world.

And then the as-yet-unharmed recipient plant might gin up an ionized-calcium engine of protection, such as producing a protein that gives insects diarrhea. I know! I was unaware insects could even have diarrhea, although I did suspect them of being able to pass frass gas.

We can sense these chemical messengers also. That wonderful, dreamy summertime fragrance of newly-mown grass loses some of its romance when you realize it’s seven million blades of grass screaming at once. It’s all MAN THE BARRICADES! ALL HANDS ON DECK! FORWARD INTO THE BREACH!

To which the neighboring lawns reply OH, FUCK! HOW, EXACTLY?

That repellent taste they can manufacture to deter munching insects has no apparent effect on a John Deere.