It's easy to germinate, and self-sows. In addition to the conditions you mention, you will need alkaline soil (dolomitic limestone is great) and some duff from conifers (chopped up pine needles, but juniper is better) in the soil mix.

It's called cedar break sage because it's found in breaks in the Edwards Plateau, These are spots on the plateau at its edge where streams have eroded a pathway, with the caliche soil breaking into boulders in the shade of Texas junipers. Duff gathers in the pockets, and these damp spots are where it can be found. I visited such a location back in the late 70s.

I replicated the conditions using hemlock needles mixed with dolomitic limestone in a small garden at my parents home in western Massachusetts the next year with great success.

Mine grow under Mountain ashe juniper trees on calcarious soil and under oaks also. They seed everywhere. now that I am encouraging them. Salvias normally like to sprout when it is warm , but I think these will sprout earlier . Mine are in dry shade, very dry shade. I do not water at all because I am on rain water and everything is limited. It takes a little while for them to size up in these conditions, but they are tough. My soil is caliche based with a limestone marl and leaf duff. I do minimal amending.. They were here before we built the house.

Rich and Mara,
Thanks for the "sage" advice. I have followed your instructions and I now have sprouts!
Thank you!