By Bruce Zaretsky
‘Early in the history of garden design – dating back to the earliest days of civilization in Sumeria, Egypt and China – plants took center stage in garden spaces.’ With that observation, Bruce Zaretsky opened his On the Level column in February 2009, then added: ‘Terraces and hanging gardens were built not for their innate ornamental qualities, but rather to display the plants they contained. Always, the prized plant was