I thought it might be fun to collect anecdotes about plants that can tell time or "predict" weather.

Such as "poor man's weatherglass", Anagallis arvensis, comes in red and blue. Flowers close unless it's pretty sunny. Just because a dude is poor, I don't think he needs flowers to close up to see that the sky has clouded over, but nobody asked me about this nickname. LOL!


Ornamental purslane has similar behavior, opening its' blooms well after sunrise and closing well before sunset. It could use the nickname "work plant" because if you work regular daytime hours, you won't see the blooms except on the weekends - but it's busy while you are, working to serve the bees.



4'o'clocks open at different times, depending on the afternoon exposure, but you know if you see them open, the day is almost over. To see the earliest possible blooms, put on the east side of the house or structure or other tall plant so the shadow will fall on it as early as possible.


One obvious one is morning glories & moonvine. Not all Ipomoeas prefer to only open their flowers after it has gotten dark and close them around dawn, but these can be a reason to get out there early and take a look around. To have blooms as late as possible into the morning, put where there's tons of afternoon sun but shade first thing in the morning.

Moonflower (Ipomoea alba)

My grandpa (in OH) pointed out to me how the silver maple trees "turn white", with their leaves flipped to show the bottoms, before it rains.

I've seen the ornamental Purslane do this in the past.

We have several huge clumps of Four O'Clocks at our cabin and they open mid afternoon. We also have Oenothera triloba at the cabin and it seems to close at night and reappears after sunrise late morning. There are spiderworts at the cabin as well. I had the giant ones (at my last house) and those closed up at night, reopening early morning. We have hundreds of the tiny Edwards Plateau spiderworts at our cabin property. I honestly haven't noticed if they close up or not at night, but will observe our next overnight stay.

My new Moss Rose 'Salmon' opens around 10am when first morning sun actually hit the pots. Sunshine has to get up over a tall oak tree first before that happens. They close late afternoon routinely and also close if it gets dark with clouds and/or rain. The other day, it was raining about 4pm, sun was peeking through the clouds for quite awhile. They closed up with the onset of rain/clouds but did NOT re-open when the sun peeked through for 10-15 minutes. That might have played out differently had the rain shower been at say high noon? I don't know.

Night blooming cereus blooms after dark and is done when the sun comes up. But if it's an overcast morning I have had them stay open until 10 or 11

This is an interesting thread, Tiffany! It doesn't exactly predict anything, but I've noticed that my PJM rhododendron leaves curl up once the temp dips below 32°F. Which will not happen any time soon, hopefully!

Evening primrose Oenothera biennis. Brilliant lemon yellow flowers open at sundown.
Interesting shaped seed pods .






Thought this would be of interest.
Plants that move on their own. Types Of Nyctinastic Plants:
https://www.gardeningknowhow.c...

Love that last photo Bea!

hastasmore….

Mimosa pudica!

All their little leaflets don't just close when touched. But once the sun starts to go down, they all fold up nice and tight.

Prayer plant..

Prayer plant.. rolls up it leaves at night, which is very cool because they're so purple on the back side.

I have read the prayer plant leafs under side is a dark magenta color because they naturally grow on the forest floor. And the dark magenta actually helps the plant capture and save light like a solar panel, rather than allow the light to go thru the leaf, it conserves the light enough to support the growth in deep shade.
Clever little plants.

Fascinating! Bea, that's the most adorable typo I've seen in a while "florist floor." We know you meant forest floor. : )

Wow Tiffany… I just caught that too! At 2:30 pm. Spell Check at it again… Well what do ya do at 5 am in the morn… my eyeballs were barely open. "That's my story and I'm sticken to it".

Works for me😏👍

Bea, it was 8:30 where I am when I posted that. You must be a west coast-er. ; )

Tiffany.. North Western coast in Oregon zone 8b. I'm a early bird….
There are a lot of debrie on the florists floor especially on Mother's Day.

I get up early too, usually just before dawn. Didn't used to be that way, but I sure am now. I feel blessed to be able to chat so easily with someone so far away and to be able to virtually enjoy your truly magnificent gardens!

the color/light is not why prayer plants roll up. it's much cooler than that..all about water retention...
they use the same red and high wavelength blue as other plants for photosynthesis, which is why the leaves are open and mostly green when the sun is out ( we see what the plant reflects.. yellows and greens and low wavelength blues that it doesn't absorb to create sugars).

at night, when there is no sun for photosynthesis, the leaves roll up to prevent unnecessary water loss through evaporation. they seal themselves up, while at the same time, allow night rain and collected dew to drip to the now exposed plants roots, where it will stay, because when the leaves open to collect sunlight again, they shade the soil around the roots to further retain moisture.. cool, no?

red wavelengths are the most easily absorbed by chlorophyll which turns electromagnetic energy (sunlight) into chemical energy needed to create long carbon sugar chains. that's why red leaves are usually saved for high cost of flowers. The red on the back of the leaves is simply efficacy. these are forest floor plants that grow in very competitive environments, they know the back of their leaves are not going to produce, because they won't ever get sun and stay low to protect their roots. .. they don't waste chemicals to stock both sides of a leaf w chlorophyll...

Makes basil look profligate, right? so clever, our mother nature.

I have a couple plants working together, taking shifts. Ornamental purslane opens when it's time for a mid-morning stretch. Then it sees the first 4'o'clock bloom open and starts to close up for the night.

my spiderwort closes after noon. neighbors evening primrose is open til late afternoon.