Robin, I also get variable blooming with my short-day salvias. Besides time of blooming, I frequently get reduced flower size, meaning the blooms are very useless for hand pollination as well as taking pictures.

UI suspect this is because I do not have a temperature regulated greenhouse with an electrically operated set of louvers, fan, and furnace. The light transmission of my glazing is probably not optimal. Finally, I pull black plastic over the greenhouse at night to cut down on radiant heat loss. When it is not used, there is a street ligh near the greenhouse that I know will interfere with sensitive plants like S. divinorum and prevent them from blooming. I no longer have divinorum, BTW!

I'll post an image or two of what some wimpy flowers look like later..

Many salvias don't like to be in pots, especially the ones which will grow large when in the ground. This is what I have learned, having moved... I have lots of plants which have been in pots for too long.

Here I a photo of S. fallax at my old place which I took about a week ago. It's quite tall and doing fine in dappled shade. The pink flower is a rare Passiflora, one of my other hobbies. ;-)