"Brandywine Cottage is David Culp's beloved two-acre Pennsylvania garden where he mastered the design technique of layering—interplanting many different species in the same area so that as one plant passes its peak, another takes over. The result is a nonstop parade of color that begins with a tapestry of heirloom daffodils and hellebores in spring and ends with a jewel-like blend of Asian wildflowers at the onset of winter. The Layered Garden...