So they're hardy, they grow impressively fast, and they're freaking huge. The label on the little packet of seeds said "12 feet tall" which I initially dismissed as marketing mumbo-jumbo. But, no, some of them really do grow to 12 feet tall in less than 2 months. And the leaves track the sun in their thirst for more juice from the sun.
And the flowers (actually, technically, they're flower heads, as the big yellow thing is actually a bunch of small flowers crammed together) are a marvel of engineering. According to the wikipedia article:
- Each floret is oriented next to its neighbor by the golden angle, 137.5 degrees;
- The orientation gives rise to a series of right-handed and left-handed spirals within the flower head;
- The number of left spirals and the number of right spirals are successive Fibonacci numbers;
- The pattern yields the most efficient packing density of seeds in the flower head.
All of which combines to form one really cute picture:
One last note: May 1st is the International Guerrilla Gardening Day, where people surreptitiously plant sunflowers hither and yon. Hilarious. I might just be an active participant next year.