Wow Robin those plants must be in a very sheltered spot, or else you live in a micro-climate.
That almost makes me want to experiment with a sacrificial Rosemary plant
We must be colder than you, but the worst things are those late freezes where a plant makes it all the way through the cold winter, puts out its spring buds and WHAM, it gets nailed by a late freeze and dies.
Sage is a perennial for me, but dies back each winter.
Linda