It’s tempting to trim the swollen tufts of lavender, each with a whisper of sweetness, that shift in the breeze on the eastern flank of Black Mountain. “But you have to be patient,” said DeAnna Schaeffer, owner of Point Reyes Lavender Company. She waits until the flowers turn a purple-gray hue before extracting the valuable oil, used in sachets, bath products, and other items. Located on an old quarry site, the land had been stripped…