I am in zone 10 (SoCal area) with a salvia "Playing the Blues" in my front garden. It's in a very sunny spot and was blooming beautifully until this week. I was told deadheading was not necessary, so I left the spent flowers alone. But then all the leaves started to brown; not just at the top, but all the way down close to the ground. I cut it back to where there was still green, leaving me with only 3-4 inches of the plant. Does anyone know what could have caused this? The plant was getting plenty of water, I fed it on the first week of each month; the only wild animals are birds and squirrels. I'm really at a loss to why this happened, especially since it happened so quickly.

Sometimes too much water may make a Salvia sick.

Did your neighbor spray herbicide that drifted?

I had to repot a salvia this morning (Salvia darcyi) because the soil got too wet. It seems to be recovering.