This map shows the USDA defined hardiness zones applied to the SW coastal area of British Columbia. What is surprising to me is that these zn 9a and b conditions continue much further north in a coastal band that includes most of the Haida Gwaii archipelago…of course the further north you go the lower your average summer high temps!  This is somewhat akin to the coastal Chilean regionThe northern end of the archipelago reaches just beyond 54ºN latitude! Much of this coastal region is rain forest.  Add up all of the shoreline along BC’s coast, and you reach nearly 16,000 miles!  Straight line distance from Victoria to Stewart, BC, the northern most point on BC’s coastline, from there north, Alaska stands between them and the Pacific, is around 600 miles. Their shoreline includes the 40,000 islands and miles of deep inlets that carve through its western edge.  Water and precipitous land define this border and explains why this region is so mild.  It is dominated by Fir and Cedar forests though the drier parts of the southern islands are home to so much Madrone and Garry Oak including Manzanita at its southern extreme. See this website.