In this thread, I think the answer is cutting back in the spring, based on my research today, even rather drastically.
I just discovered these delightful salvias, including Hot Lips, which I saved from a plow in an annual community garden about 3 weeks ago. Regarding cutting back, spring was recommended by this Irish gardener / business owner via "John Lord's Secret Garden" entitled: How to Look After Salvia 'Hot Lips' and Similar Varieties. He demonstrates cutting back in the spring and repotting:
The 5 varieties mentioned in his video:
Salvia greggii 'Amethyst Lips',
Salvia 'Dyson's Joy',
Salvia microphylla 'Blue Monrovia',
Salvia x jamensis 'Pink Lips',
Salvia 'Hot Lips'
It was good to see how much he cut it back (a lot) and when. I imagine his climate is closer to Zone 8 than mine. As I'm in Michigan 6a, I researched salvias a bit as I was making sure I had some softwood cuttings to overwinter along with planting my Hot Lips Salvia in a protected spot surrounded by fennel, and hoping for the best.
The link: https://youtu.be/2vA9uQx_5oE
Marilyn said:Hi @fstins1
If and when I cut salvias back, it is very late spring or later in the season for my zone 6a. For you in zone 8b, I don't know.