Does rosemary even get sick?

Does rosemary even get sick?

I have a potted rosemary plant that's been having random leaves yellowing and dropping off all season. I thought it was lacking in nutrients, but several applications of fertilizer haven't affected it at all. Also, before falling, the leaves develop purple specks that leave the surface looking like a mosaic. I can identify most common garden diseases, but I never hear about rosemary coming down with problems the way roses or tomatoes do. Anyone have thoughts on what it might be? Should I cut the plant out and try another one next spring?
What to do?

What to do?

Bathroom Makeover :)

Bathroom Makeover :)

Dahlias

Dahlias

Bar help!

Bar help!

IDs please and thank you

IDs please and thank you

Mystery Corner

Mystery Corner