Editorial

Jo McCarroll reflects on plants.

Ihardly need tell you, dear reader, that plants are extraordinary things, capable of vastly more than most people know and living lives of far greater complexity than humanity has even begun to suspect.

Studies have shown they can respond to sound, for instance. Playing plants an audio recording of a bee buzzing will stimulate pollen release, while scientists have found plants exposed to the vibration caused by a caterpillar chewing produce more bug-repelling chemical toxins in their leaves than plants exposed to the vibrations caused by wind.

Plants can communicate, and in a variety of ways too. They send out electrical distress alerts, release chemical signals into the air and the soil, and pass on messages via the vast underground network of mycorrhizal fungi (or, as it’s sometimes called, the Wood Wide Web).

And while plants don’t have anything like a memory, they act in ways influenced by past experiences. An Australian scientist designed an experiment where she dropped Mimosa pudica plants like they were on a roller coaster. To begin with the leaves of what is called the sensitive plant – which famously curl up in response to a touch – would close up tight. But as she repeated the experiment on the same plants, the leaves stopped responding. Effectively, the plants seemed to “learn” that dropping was nothing to fear (and tests a month later found the same plants “remembered” the experiment and didn’t respond if dropped).

Plants can recognise family members. Studies have found a difference in root growth between seeds grown in a pot with other seeds collected from the same parent, and seeds grown with seeds from the same species that were collected from a different plant (interestingly, research is unclear on whether that’s because related plants play nicely together or are simply happy to gang up against a common threat. Which proves, to me at least, that siblings are the same across the whole biosphere).

Plants even give each other personal space. Some trees reign in growth in crowded conditions so the crowns of the mature canopy don’t touch (this phenomenon, known as canopy shyness, can be seen between the redwoods in Whakarewarewa Forest near Rotorua). It’s theorised leaving the gaps between the trees helps prevent the spread of pests and diseases between them, so basically trees have been socially distancing for ages.

But despite knowing all this I was floored to read a suggestion from

Rick Karban, a University of California entomology professor who has spent decades researching the field of inter-plant communication, that plants could be shown to have their own individual personalities.

Previously botanical science has assumed that plants in a species were effectively replicants and would respond in the same way to the same things. But demonstrating a diversity of responses might, Professor Karban suggests, benefit a species as a whole. So one plant might be hyper-alert emitting distress signals at even a whiff of danger, another plant of the same species in the same situation might be more laid-back.

I would love to hear your thoughts on this, my best beloveds. Do you detect different personalities among the plants in your garden? Have you noticed a rhododendron that’s a show pony, an impatient impatiens or an introverted ivy? Are you growing a noticeably conscientious cornus or a particularly neurotic nasturtium? I am not saying that Professor Karban’s theory is right, but I am not saying it is wrong either. Because one thing I know about plants – perhaps the only thing I know for certain

– is they never lose their ability to amaze us.