If you have a couple...........let one go to seed, and dead-head the other! Even with dead-heading, this Salvia can still behave as a biennial. Sure you are aware, but take maximum precautions against slugs and snails, it is their S. divinorum!

Asexual propagation is not easy with this species...can be done from new shoots, but success rate not good.

Re crossing, certainly possible if you grow other Salvias from similar regions...Eastern Europe and North-West Africa ...in close proximity.

Grown from seed, flower spikes appear in the 2nd year.

I second what Robin has said, but add that in Denver and the rest of the Front Range of the American Rocky Mountains, it behaves as a true perennial. Some plants have reached 15 and even 22 years!

The Eurasian steppe sages do fabulously there. This means those from the central plateau of Turkey, Iran, as well as Russia and the former Soviet states to the west of India.These can be very hard to do on the east coast of the USA, especially the subtropical southeastern states.