If you want to add some botany and some poetry to your science, why not try something that was first proposed by Carolus Linnaeus? You can have a zero-carbon-footprint clock made of flowers.
What happens if you wake up one morning and find that it's too cloudy to get a clear reading on your sundial? I'm guessing you would then go to your wind-up clock, your digital clock, your cell phone, the TV news, the radio, your laptop, and the little blinking clock on your microwave that went out in the last black-out and you've never bothered to reset but you kind of know how far off it is.
But what if all of those options were gone or you just want to have the classiest clock in the neighborhood? Then you should follow the example of Carolus Linnaeus. He was a botanist, zoologist, physician, and the father of taxonomy, so you know he had excellent time-management skills. Vexed with his sun dial, he came up with a flower clock. Many flowers open at different times of the day, and by watching these flowers bloom, he managed to come up with a schedule by which he could tell time by seeing which flowers were opened and which were closed. It was quite complete. Night-blooming cereus opens, for example, at 10:00 PM and closes at 2:00 AM. The four hour interval between is a mystery, but the rest of the day is as documented as anyone who isn't nocturnal could wish. At five in the morning, the morning glories open (maybe attach a bell to one or something to make it into an alarm clock). Most people have to get to work by the time the African daisies open up. Lunch break is when the morning glory closes. There's even a plant so known for its punctuality that it's call the Four O'Clock Plant.
Here's a full list of plants to tell time by. Stock your garden with them and preen in front of any people who measure their love of nature in hikes and granola.
Image: Benson Kua