Salvia Mystic Spires Blue (S. longispicata x farinacea) sounds like Indigo Spires to me. Do you know the source of this hybrid? It might be a new cross or some nursery might have simply rebranded Indigo Spires to enhance marketing potential. I've seen this go on with S. guaranitica.

Indigo Spires does not set seed as far as I know, based on my own experience, the experience of a lot of botanic gardens and nurseries I visit, and any posts I've seen on the Salvia groups on Garden Web and Yahoo.

If you are lucky enough to get seed, these will be F2 hybrids, which can vary all over the spectrum from one original parent to the other.

See my thread "Saving seed of New World Sages" for your last question. It's on the second page of posts.

Good luck! You will do better in a more Mediterranean climate than a subtropical one.

Rich,

It is a dwarf version of Indigo Spires. here is the link to the company that branded it.

thanks,
xman

Here is a link that might be useful: Salvia Mystic Blue