This is a very interesting Flower Clock based on observations made by Carl Linnaeus, the dude who is considered the Father of Modern Taxonomy . . . that is, he is responsible for a lot of those tongue twisting Latin names attached to every single plant.
You know; the names that some plant geeks like to spout off to impress the non-botanist of the World. Though I must say there are a lot of plant geeks who know more than just every Latin name for thousands of plants-they actually know where they go and how they go in . . . at any rate I digress from my main point.
More about Linnaeus, and the constant fighting over taxonomy at a later date . . .
On to the main reason for the post . . . the Flower Clock:

[Image found at the Proceedings of the Athanasius Kircher Society site]
From the Linnean Society of London on the Flower Clock:
Linnaeus’ Floral clock
Linnaeus observed over a number of years that certain plants constantly opened and closed their flowers at particular times of the day, these times varying from species to species. Hence one could deduce the approximate time of day according to which species had opened or closed their flowers. Arranged in sequence of flowering over the day they constituted a kind of floral clock or horologium florae, as Linnaeus called it in his Philosophia Botanica (1751, pages 274-276). A detailed and extended account of this in English will be found in F.W.Oliver’s translation of Anton Kerner’s The Natural History of Plants, 1895, vol.2, pages 215-218. As many of the indicator plants are wildflowers and the opening/closing times depend on latitude, the complexities of planting a floral clock make it an impractical proposition.
The idea was taken up by the French composer Jean Français in his composition L’horloge de flore and the following list gives the hour of the day, the French names, the botanical and English names of the plants he chose to represent in music:
Linnaeus; in writings titled Philosophia Botanica wrote about 3 types of flowers:
- Meteorici, A category which changes their opening and closing times according to the weather conditions.
- Tropici, Flowers which change their opening and closing specifically to the length of the day.
- Aequinoctales, Most important here to this story, are the flowers having fixed times for opening and closing, regardless of weather or season.
Now concerning the Aequinoctales flowers. Linneaus published in 1751 the Philosophica botanica a list called the “Horologium flore“. Which I found in several different places:
0200 – Night blooming cereus closes
0500 – Morning glories, wild roses
0600 – Spotted cat’s ear, catmint
0700 – African marigold, orange hawkweed, dandelions
0800 – Mouse-ear hawkweed, African daisies
0900 – Field marigold, gentians, prickly sowthistle closes
1000 – Helichrysum, Californium poppy, common nipplewort closes
1100 – Star of Bethlehem
1200 – Passion flower, goatsbeard, morning glory closes
1300 – Chiding pink closes
1400 – Scarlet pimpernel closes
1500 – Hawkbit closes
1600 – ‘Four o’clock’ plant opens, small bindweed closes, Californian poppy closes
1700 – White waterlily closes
1800 – Evening primrose, moonflower
1900
2000 – Daylilies and dandelions close
2100 – Flowering tobacco
2200 – Night blooming cereus
Knowing that we have access to hundreds, and hundreds more species, and a much larger knowledge base I’m sure this list can be easily expanded. A Designer looking to create a Flower Clock and have some Historical anecdote thrown into the design would use plants from this list-changing out to modern cultivars improving the design.
Is a clock like this practical-hell no, if you want to create an exact interpretation. But, I could see a time and a place where someone(client) would like to have something like this designed into there landscape-maybe even a simpler version . . . think of . . . something clever.
This might be some good info to pass onto that mad-gardener friend of yours. Something they would just have to have. Maybe . . . just maybe you know a Linnaeus nut . . . or someone who is just mad over taxonomy . . . what’s that? Yeah, but you never know.
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Addendum: Confused about the difference(s) between the meaning of Taxonomy and Nomenclature, I hope this helps.
Here is a link to a much larger black&white image of the clock illustration. The one thing I am unsure about is whether or not Linnaeus is responsible for the actual illustration.
Sing it brother! Yes! I LOVE this stuff!
What the world NEEDS is a the Horologium flore surrounded by some of your stonework!
And by the way, you realize of course that Linnaeus concieved of the world as divided into THREE kingdoms: Plant, animal and stone. PERFECT FOR YOU!
My question is: “Why WOULDN’T anyone be a Linnaeus nut?”
The three kingdoms he specified were the animal kingdom (Regnum animale), the plant kingdom (Regnum vegetabile) and the “mineral kingdom” (Regnum lappideum).
are he sure that flower clock will work??? why there is some time spot that are missing of floral counterpart??? THAT IS NOT ACCURATE!!!
this is really cool!!!!!!!!!!!!!!! i think im gonna try nd find the floral clock for my area….
where can i buy a horologium florae clock?
Im not that much of a online reader to be honest but your blogs really nice, keep it up! I’ll go ahead and bookmark your site to come back later. Cheers cfcaekdeeeca