Amazon.com In another life, Penelope Hobhouse could have been an architect. For the garden designer is at her best explaining the bones, or living architecture, of the garden. As she walks the flower walk at breathtaking Longwood Gardens in Pennsylvania, she's so enthusiastic, she barely allows curator Rick Darke to speak. She sees gardening "as a sort of a theater," and Longwood is an excellent example of the structural elements of design with its hedges, alleys, avenues, and topiary gardens that reflect light in interesting ways. Her designer's eye is also evident in the second half of the program, where she explains how to successfully blend annuals, perennials, and biennials in a summer garden. Flower-by-flower, you learn how a yellow border at Hadspen House in Somerset was cultivated before traveling to New York, where expert Caroline Burgess explains the thought that went in to planting two distinctly different gardens at Stonecrop, a 40-acre estate. --Valerie J. Nelson