This past spring I had a row of rosemary planted along the top of a 5' retaining wall on the SW front of my house. Fully sun most of the day. During the summer I had three die suddenly. (they were random, and not all in one spot). Wrote that off to infant mortality or improper planting. However, today, I noticed that quite a number of the others have branches that are turning a brownish gray, and that the leaves on these branches, even when still green are looking wrinkly. Could this be freeze damage, water damage, a little varmint, or no big deal?