Unless you never step outside or watch the news, I am sure you’ve probably noticed that the United States is experiencing a wicked deep freeze. It’s the kind of cold that freezes your boogers instantly and necessitates a heavy jacket, hood, scarf and deep pockets, preferably fleece lined and heated. (Hey! Great idea, someone should make those!) At my house this morning, in western North Carolina, it was a whopping 4 degrees! Before even stepping foot outside, I knew it was cold, just by LOOKING outside and noticing the leaves of a certain plant.
That might sound a bit implausible but it really is true, at least to a degree. So even if I never watched TV or looked at the weather for the day with my weather App, I could look outside and know that WOW, it’s a long-underwear and turtle neck, heavy sweater day. Or even better yet, maybe it’s a -let’s-stay-inside-by-the-fire day, and there’s-nothing-you-can-say-to-get-me-outside day.
I know this not because I have leaky windows, or no walls on my house, but because the Rhododendron leaves on the bushes surrounding my house are drooping and curled so tightly I doubt even a pencil would fit in the middle. I am cold just looking at them!
Did you know some plants, like rhododendrons, are thermotropic? This means that they have leaves that are temperature sensitive. When it is 40 degrees, their leaves are flat and horizontal. When the temperature drops below 32, their leaves drop to be vertical and on days like today–when the temperature is below 20, the leaves curl up in a tight ball.
There is a lot of speculation from scientists about why they do this and theories abound. After some research of my own, I can say that the general consensus at this point is that they curl and droop in order to prevent damage to their cellular membranes. Of course then one might immediately ask, well, why then do other plants not do this? What is it about the structure of a Rhododendron leaf that is different? I can’t answer.
For me, it is enough to know I can glance outside, notice the leaves of the Rhododendrons, and make a sensible clothing choice. Not exactly rocket science, but it is another pretty interesting thing about the adaptations that Mother Nature has developed.
Today I will be content to admire nature from INSIDE my cozy house.