Lavender is a bit iffy here. It isn't the cold, but the warm muggy nights. Also it may get too much water (wet feet), especially if a garden with other things that need some water. Sometimes I just treat it as a short lived perennial, much as I do regular sage.
This plant in question had some problems, and I cut a bunch of it out, and it came back prettier. This last bout of going south is branches going grey -brown-dead. Or splitting at the main stem. I try to cut out the bad branches. To complicate matters the healthier part is growing into another plant I am encouraging to spread. And it is not pretty in its current state; just waiting for the blooms to finish!
OK, I know, I need another raised bed just for the dry feet plants. This will be raised, have sandier soil, in the sun. I can put lavender, sage artemesia (wormwood, southern wood) and a few other lovelies in it. I can't keep up with what I have. What was I thinking?!