I divided this blue ensign salvia three years ago and replanted two small clumps of it same spot

I do that it may 1

It's almost sept first temps next week are 90 to 92 and humid sunny

Our first freeze is nov or frost
We get about one could be nov 9

Would you wait till spring to dig it all up and put down some black kow and new soil mixed in and plant a outer pieces that are newer shoots?

Or do it now sept 1?

I cut it back during our past two weeks when we had cloudy days and rain to not put it into shock

I usually prune it March every year
Leaving the dry stems over winter

Pic below of it trimmed
But not moved or divided
Till I hear from you
It's zone 8b
Blue ensign salvia

It never has yellowed till this summer July was 105 heat index many days
Did it get too stressed or need fertilizer and what type and how often

I had read to not fertilize perennial salvia and never do

It gets morning and mid day hot sun

It's a soil bought and my black soil deep down clay way down not where roots are

Any thoughts on yellowing and my first post on digging some up and replanting two small newer shoots
In this spot ?