Looks like another Rosemary plant didn't survive the winter. This one was the Blue Spires variety. According to the label, it is supposed to be cold-hardy to Zone 6. Since Coquitlam is Zone 8, I assumed it would be okay. I think Blue Spires is one of the most cold-hardy varieties available. Only the ARP variety might be more cold-hardy. After losing a Rosemary previously, I put this one close to a creek, hoping the water would moderate temperature a little. And in the Autumn a lot of leaves were raked around it, hoping decomposition might provide a tiny bit of warmth. It still died. Darn! There is some good news though: the two plants in a pot under the garage eave seem to be doing fine. They are south-facing so they get a full day of sun. And being under the eave lets me control the water better. Over the winter, I gave them a pot of day-old, cold, tea once every four or five weeks. In the Autumn, they too got some leaves stuffed around them, held in place with a brick. Later this Spring, I am planning to transplant these two plants into individual, bigger, pots. Lesson learned: keep Rosemary in pots, so they can be moved against the house in winter.
In BC you're going to have two different hardiness zone systems in effect, the Canadian and the USDA. And they do not dovetail. Making which a source is referencing significant. Otherwise, the same topography through which moving water drains often serves as a drainage corridor for cold stale air also. With it being bodies of salt water than can affect temperature regimes. By absorbing heat during the day and releasing it at night. With their salt content being what causes this to happen. Finally, it only takes a few hours below a given plant's minimum temperature for it to burn up. And plants that have not been grown in a manner that enables them to achieve their full hardiness may often fail at higher temperatures than they would otherwise. With rosemary being a Mediterranean shrubland plant adapted to hot and dry summers, mild and rainy winters. And open aspects with plenty of sun exposure.
Unfortunately, wet soil hinders hardiness in Rosemary; you'd do better to plant it on a well-drained mound of sandy soil. And ditto a lot of leaf mould in the soil! Again, a mineral soil with low humus content would improve its hardiness, as it slows growth down. Sappy young growth in autumn encouraged by fertile soil is a recipe for cold damage.
