I think you could call it a tradition by now for me to introduce our readers to weird plants in the winter months. Once the gardening season is truly at a standstill, which usually happens in December and January, my eyes open again to the beauty and charm of my houseplants.
When I’m at the garden center, I don’t rush through the houseplant section just to get to the outdoor plants, as I usually do in spring and summer. I somehow have enough bandwidth to focus on finding houseplants such as the Mimosa pudica that I’m going to tell you about today.
However, my first encounter with the sensitive plant was not when I put it in my cart at the store. I had seen it before, numerous times, taking its pride of place in glasshouses at various botanical gardens. And perhaps more relevantly, I had touched it before and I knew what to expect!
But why does it matter if you touched it or not, Mickey?
Ok, so I’m not that weird about houseplants so as to turn touching them into my whole personality. But the quirk of this plant is that it literally reacts to the touch.
Have a look at this video I took to see what I mean.
Isn’t that the coolest houseplant thing you’ve ever seen? I love a plant that can pull off a good party trick.
This is called seismonastic movement and it is a reflexive response to various stimuli such as touching, shaking or blowing on the leaves of the plant. Tiny microscopic hairs on the leaflets of the Mimosa pudica send signals to the base of the leaf that there’s some sort of danger. Then the base sends signals back to move water out of these cells very quickly.
It’s this almost instantaneous cut off of the water supply to the leaflets that causes them to fold up. Nature is lit, as the internet kids say! It won’t stay stuck like this forever, but it does take it some time to unfurl again at a much slower pace.
Mimosa pudica goes by a few nicknames.
I’ve seen Mimosas go by a few nicknames, all inspired by its dislike of being touched. Names such as the sensitive plant, the shy plant, the humble plant and touch-me-not.
Commercially, I’ve only ever seen it referred to as ‘the sensitive plant’ which sounds much more appealing than the other nicknames, I think. Although ‘the bashful houseplant’ also sounds endearing.
And just in case you’re wondering, there’s no connection between the mimosa plant and the mimosa cocktail. The cocktail, which uses orange juice as a mixer, was named after the equally orange mimosa tree (Acacia dealbata).
Is this weird Mimosa pudica a rare plant?
That depends on who you’re asking.
Mimosa is a tropical plant – like most of what we call houseplants nowadays – native to South and Central America. It’s also a very common outdoor plant in South-East Asia, Australia and South Africa.
Friends who were born in Southern US states tell me that they remember how they used to play with these plants in their gardens when they were kids. In some tropical regions, it’s even considered invasive. So if you live in one of these areas, definitely only keep it as a potted houseplant.
I’ve only ever lived in temperate climates, and I don’t think I’ve ever seen the sensitive plant outside of a botanical garden context. So if you ask me, it is an unusual plant to have. And it’s becoming quite a conversation piece with guests.
Although I should probably come up with less weird ways to say “Wanna see what happens when you touch this plant?”
How can I keep my Mimosa pudica alive?
First, let me put your mind at ease. If you’ve just brought your sensitive plant back home and it looks dead within the span of a couple of hours, you’re in the clear. You did not just break the world record for the fastest person to kill a houseplant. It may just be a bit shocked from all the changes, and it will recover.
Mimosa also closes up at night and opens back up in the morning. This adaptation to the circadian rhythm is called nyctinasty.
It does this in order to prevent moisture loss when the plant isn’t actively getting sun for photosynthesis. This nap also protects the plant during the colder night time.
Just set your plant in a sunny windowsill and you’ll see that it opens up again at the break of daylight.
In true plant detective fashion, we can make a few deductions based on this nighttime closing behavior:
- The sensitive plant protects itself against moisture loss at night, so it needs moisture;
- It protects itself against cold, so it prefers a warmer environment;
- And it opens up to take in as much light as possible, so it definitely likes sunlight.
If we manage to get all these factors just right, the sensitive plant will reward us with a small cluster of flowers – or just one larger flower – in the summer. The flowers of the mimosa look like fuchsia-colored pop-poms that seem almost translucent.
Here’s what you need to keep your mimosa happy:
Plenty of humidity
The sensitive plant likes moist soil – not the same thing as waterlogged soil, mind you. I water mine by placing the planters in a bowl of water for about twenty minutes every week. That gives it enough time to soak as much water as it needs.
Mimosa also likes higher humidity. This means that regular indoor humidity – at a level that’s comfortable for us (roughly 30-50 percent) might not be enough. Around 60 percent might be more to its liking.
You don’t have to turn your home into a sauna to keep this plant happy. The easiest solution is to place it in spots that generally get more moisture, such as bathrooms, kitchens or sunrooms.
I keep my mimosa on a plant shelf next to the shower, in good company with other humidity-loving plants such as the crispy wave fern.
A relatively warm environment
Again, no need for a sauna. But you can’t keep it in a cold guest bedroom either. Keeping the sensitive plant in your shower room or your kitchen might take care of this conundrum too. The optimal temperature should not dip below 65F (around 18-19C).
And remember to keep it away from drafts. This includes not just those from open windows and doors, but also fans, floor vents, chimney flues and air conditioning.
Plenty of light
This is where it gets a bit tricky, because the quirky Mimosa pudica doesn’t do well if it’s not getting enough light. Direct light is best, but indoors that’s only possible at the height of summer where I live.
The best that I can do for my sensitive plants is place them in windows that get bright indirect light and they seem to be ok with the compromise.
Can you overstress a Mimosa pudica?
I mean, wouldn’t you be stressed if somebody kept touching you to provoke a reaction?
So while showing this party trick every now and then to unsuspecting guests is an acceptable level of stress, brushing against it repeatedly is not. The more the plant is forced to fold up, the more energy it wastes. Not only that, but every time the leaves close, the plant misses out on photosynthesis.
Either you cut it out, or the plant will.
That’s right – if you overstimulate it, it will stop reacting. Researchers tested this by repeatedly trying to obtain a reaction from sensitive plants either by dropping them or dripping water on the leaves. Once the plant learned that the disturbance wasn’t a real threat – there was no real damage to the leaves – it stopped reacting.
What’s fascinating is that the sensitive plant remembered this learned behavior for a month, even when the researchers were no longer repeatedly disturbing it. After weeks of being left alone, it would still not react to the touch.
Yes, you can “break” your mimosa if you overdo the tickling. [Which sounds like a perfectly normal phrase to end an article with.]
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