Rosemary Verey was the last of the great English garden legends. Although she embraced gardening late in life, she quickly achieved international renown. She was the acknowledged apostle of the “English style,” on display at her home at Barnsley House, the “must have” adviser to the rich and famous, including Prince Charles and Elton John, and a beloved and wildly popular lecturer in America. A child of a generation born between the two World Wars, she could have easily lived a predictable and...