6GREEN D. Perennials all Season [M]. Chicago: Contemporary Books, 2003.
7DISABATO-AUST T. The Well-Designed Mixed Garden:Build- ing Beds and Borders with Trees, Shrubs, Perennials, Annuals, and Bulbs[M ]. Portland, OR : Timber Press, 2003.
8TURNER R. Design in the Plant Collector's Garden [M]. Portland, OR :Timber Press, 2005.
9TAYLOR P MOLESWORTH C. Making Gardens:Patrick Tay- lor's Essential Guide to Planning and Planting [M]. Portland, Or: Timber Press, 1998.