Washington State initiated the Master Gardener program in the 1970s as a way to better serve home gardeners by training experienced gardeners to teach others through the Cooperative Extension system. A quarter-century later, the program has spread throughout Washington and many other states. The Master Gardener Extension programs in Washington and Oregon offer their training manual as a basic gardening text and resource for gardeners throughout the Northwest. The Sustainable Gardening Handbook, OREM8742, was first published in 1999 and revised in 2003. It is 536 pages, and sells for $30.00. Order through the Bulletin Office, Washington State University, Box 645912, Pullman, WA 99164-5912. Or order online: http://cru84.cahe.wsu.edu/cgi-bin/pubs/OREM8742.html.
Favorite or New Plant
Centaurea 'Colchester White'
Centaurea cineraria 'Colchester White' is the best silver-leaved plant I've seen in years, and it's great for adding frosty foliage to containers and borders. Its intricately cut leaves resemble those of the bedding annual dusty miller (Senecia cineraria), except that Centaurea cineraria 'Colchester White' produces a large, elegant, arching mound of foliage 18 to 24 inches tall and wide.
'Colchester White' is related to the annual bachelor button. It bears pale lavender-blue pincushion flowers on lanky 30-inch stems in late spring. I gather these for bouquets or simply remove them, because if they're left to grow, they quickly sprawl and pull the plant open at the center.
In my garden, 'Colchester White' resides in a well-drained raised bed, combined with deep-purple Stokesia 'Purple Parasols'. These two sun-loving plants weave themselves together so that the purple Stokesia blossoms appear to belong to 'Colchester White'. This plant is also a great candidate for containers, where its wandering stems wind among other plants. It is hardy only in zones 8-10 so I treat it as a tender perennial. When autumn frost approaches, I take cuttings, root them in perlite, and overwinter the plants in a sunny windowsill.