color of a hydrangea bloom often depends on the pH of the soil. Dad's are usually pink, being in central Indiana, but he acidified the soil this year to produce these gorgeous blue-purple blooms. They're absolutely stunning. He clipped one to bring inside, so I took it back out into the late-day sun and spent at least 10-15 minutes photographing it from every possible angle.
This influence on colors reminds me of the science experiments we sometimes did in elementary school, where we put a white carnation in water that included food coloring. As the flower drank the water, the petals changed color.
Thinking about that makes me want to turn on PBS and watch kids' shows!
Camera: Canon 40D with 60mm macro lens, 1/250s, f/4 at ISO 100 at about 6:30 p.m.