One June day in 2014, Beth Robertson-Martin found herself standing on a dirt road dividing two California tomato fields. On one side sat a farm that was nothing more than a 300-acre carpet of dried-out dirt. "It looked like a scene from Mad Max," she remembers. "Everything was dead." On the other side was a 6-foot-tall hedgerow, a tangle of white-blossomed milkweed, sunflowers and elderberry bushes that General Mills had planted alongside the tomatoes to create a habitat for bees, butterflies and other pollinators.