“It’s dead; it’s most definitely dead,” I said. “How could it be dead? It was alive a few hours ago.” my husband asked. “I don’t know but look at it; it’s brown and limp and most definitely dead,” I responded. “Well, you don’t have the best track record with potted plants,” he said sheepishly. “Yes, but killing one within hours of having it in my possession? That’s a new record!” I exclaimed.
Let me catch you up to speed on the situation. A few hours earlier, as we said our goodbyes, my friend handed me a plant as a gift. At a previous visit, I had admired one just like it in her home. The plant was unique; I’d never seen one at a greenhouse or nursery, and after inquiring about its care, I was anxious to get my new plant home. I crossed my fingers, hoping that it would fare well during the hour-long car ride.
During the ride, we were extra cautious around turns and over bumps so as not to disturb the delicate plant. I checked on it occasionally, glancing into the back seat as we drove. All seemed well until we arrived home, and I took the plant out of the car. It was dead, most definitely dead. The branches drooped, and the leaves were brown, making the single central stem look like Charlie Brown’s Christmas tree. With trepidation, I gently touched one of the branches, and several leaves fell off. Yep, it was dead, most definitely dead. I had failed yet again, in record time, to keep a potted plant alive. What would I tell my friend who had so generously gifted it to me? Ashamed and crestfallen, I placed the plant on my windowsill and went to bed.
The next morning, I awoke and remembered the dead plant in my living room. Should I make it a tombstone engraved with “RIP poor little plant that had the unfortunate luck of coming into my care”? I’d have to get on that, but I had to dispose of the remains for now. I dragged my feet and prepared to cringe upon seeing the decrepit foliage. Instead, I stared, unbelievingly, at a beautiful, and very much alive, plant! Every branch stood rigid, outstretched with vibrant green leaves, and there was even a new pink flower that sat atop the central stem like a star on the Christmas tree. “What kind of zombie plant is this?” I exclaimed.
It turns out it is called Mimosa pudica, commonly known as a sensitive plant, humble plant, or shame plant, and a native to South and Central America. I knew that sensitive plant leaves close when touched, only to reopen minutes later, a monumental feat that they accomplish by rapidly releasing water from special cells at the leaflet base. However, I didn’t know that the plant also has nyctinastic movement, a phenomenon where the branches and leaves droop and close in darkness, only to reopen in daylight. Scientists believe that this is a defense mechanism against browsing herbivores. The undersides of the leaves, having a brown hue, appear dead when closed and limp. It’s no wonder I thought it was dead, definitely dead.
I’ve had this plant in my possession for a little over a week now, and it fascinates me. The slightest touch or breeze will cause the branches to droop and the leaves to close rapidly. It is captivating (and a little bit creepy) how reactive this plant is to touch. Habituation studies have shown that with repeated mechanical stimulation, there is a decrease in sensitivity, leading scientists to believe that the plant has the ability to learn. A reduction in sensitivity when exposed to repeated touch makes evolutionary sense, as the plant can’t afford to expend the energy required to close all of its leaves every time the breeze blows. A plant that looks dead only to come alive the next morning, reacts negatively to touch, and can evolve and learn? It sounds like every sci-fi zombie movie I’ve ever watched!
Regardless of its many monikers, in my house, the sensitive plant will forever be known as the Zombie Plant, ‘dying’ each night only to come alive the following morning. What a unique and fascinating plant! I’m thankful that I didn’t cause this marvelous plant to become deceased (yet) and even more grateful that it eats fertilizer instead of brains!
Abramson, Charles I. & Chicas-Mosier, Ana A., “Learning in Plants: Lessons from Mimosa pudica“, Frontiers in Psychology, 31 March 2016, https://www.frontiersin.org/articles/10.3389/fpsyg.2016.00417/full