In the United States the indigo flower became an important commodity crop to make blue dye; it was mostly grown on Southern plantations and often by enslaved people. The petals must be collected by ...

Producing indigo dye is a bit like making beer, she explained, as we piled into her indigo Subaru. The leaves are steeped and fermented in water but that doesn’t produce the breathtaking color.

Natural indigo dye has been used worldwide for thousands of years, but the invention of synthetic indigo dye in the 1800s caused the industry to crater. In Japan's Tokushima Prefecture, ...