Ok, they’re not people, but they certainly have a lot more in common with humans than most of us realize. I know it sounds sort of New Age-y, but the fact of the matter is that plants are living things and as such, there are some things they do that are more than a little bit human-ish.
Here are just a few of the ways in which plants and people are more alike than you may care to admit:
Plants Have A Life Span
This is one that I assume most people probably know in the back of their minds, but don’t give much thought to. The reason I think that is that when I tell a person the reason their tree or shrub looks rough is because it’s reaching the end of its natural life, I often get a pretty surprised look back. But of course, if plants didn’t have a life span and they just lived until, the planet would be a bit overrun with them, right?
Annuals have a life span of one year, biennials have a life span of two years and perennials have a life span of more than two years. That’s assuming they aren’t killed by an external force, whether it be a bug, disease or well-intentioned but slightly overzealous gardener.
Most trees and shrubs have a lifespan of at least a decade or so, but there are plenty out there that can live for hundreds, even thousands of years. Desert plants often have a very long life span, including local species like creosote, dwarf Joshua trees and bristlecone pines. There are bristlecone pines that have been around for over 5,000 years and creosote rings more than twice that old in this part of the world.
Plants Get Hormonal
Plants produce hormones in order to regulate their growth, flowering and aging and, just like in humans, their hormone levels are delicately balanced. You’d be surprised how easily production levels can be altered, which can make a plant much more susceptible to pests and disease. Too much fertilizer could force a tree to put more energy into producing new growth and not enough into producing the chemicals it uses to defend itself against bugs. Not enough water and a plant might not be able to produce the hormones it needs to ward off a fungus.
Plants Can Communicate
In recent years, scientists have found that plants communicate with one another through an underground fungal system they’ve dubbed the “Wood Wide Web.” Not only can plants of the same species communicate with one another, it also appears that different species are able to send and receive messages through this network of fungus. In some cases the communication is used to help other plants survive, but there are also instances where the communication is used to steal nutrients or keep another species from thriving.
In addition, a study by a researcher at Virginia Tech’s College of Agriculture and Life Sciences last year determined that some parasitic plants communicate with their host plants above ground. The study found that dodder, which penetrates host plants like tomatoes and Arabidopsis so it can suck out their nutrients and water, first sends a message to its victim, telling it to lower its defenses. It’s really hard not to imagine dodder stroking the leaves of a tomato plant and whispering, “It’s okay, baby, this won’t hurt a bit,” when you read about this kind of thing.
I think most people do realize that plants breathe, but I don’t think they realize that it’s done through the leaves, stems and roots. That’s why so many people kill their plants through overwatering. They tend to think of overwatering as something that happens from putting too much water on a plant at one time, but if it has decent drainage, it’s nearly impossible to give it too much water in one drink. Overwatering is actually what happens when a person waters their plants too often. If the top layer of soil stays wet all the time, air can’t reach the roots and the plant will eventually drown.
Plants Have Their Own DNA
When people want to know why one of their Texas privets is growing slower than the other one that’s right next to it, this is usually the answer. They were both planted at the same time and they’re both getting the same amount of water, fertilizer and sunlight. Why on earth shouldn’t they be the exact same height? Well, for the same reason that you and some guy who was born in the same hospital you were, on the same day, who lived in the same city and ate a similar diet may not be the same height. You each have your own DNA.
When I first started reading descriptions of trees, I thought it was mildly hilarious when I’d see one that would say a particular species gets between 40’ and 70’ high. That’s a pretty broad range, is my thinking. But I finally realized that it makes sense if you think of the fact that average human height ranges from under 5’ to well over 6’ tall. The range for trees is just on a larger scale. Of course, nutrition and growing conditions can have an impact on the height of both tree and people, but DNA plays a pretty big role as well.
Plants Can Hear
Well, they can hear vibrations at the very least. When University of Missouri Columbia researchers played back the vibrations made by a caterpillar munching on leaves, they found that plants responded by producing defensive chemicals that would make them taste less appealing to bugs. The plants didn’t produce the chemicals when they were exposed to vibrations created by other insect noises or the wind, which indicates that they can tell the difference and react accordingly. Now the next time a self-righteous vegetarian starts in on you for enjoying a steak, you’ll have a little extra ammo in your arsenal.
Plants Have Memories
An experiment run by animal biologist Monica Gagliano showed that some plants can learn a lesson fairly quickly and hold the memory for longer than some insects can. Gagliano used a mimosa plant, which resembles a fern and which curls its leaves up when it’s disturbed, for her study. The researchers found a way to drop the plant a short distance without causing any harm and the first few times, its leaves would contract, just as they expected. After five or six falls however, the plant stopped collapsing its leaves altogether. It seemed to recognize that what was happening was not a threat. Gagliano and her team wanted to ensure that they hadn’t simply worn the plant out though, so they shook it in order to provide a different type of disturbance. The plant immediately curled its leaves again.
What’s most remarkable about this experiment is that they continued to run the test on the same plants every week for a month and the plants appeared to retain the lesson the whole time. It didn’t react to being dropped, but it did still respond when it was disturbed in other ways. Frankly, I know people who can’t learn a lesson that quickly or remember it for that long.