This plant is not often seen in Australia and certainly rarely sold. It would most likely be in the southern states if it was, I doubt if it would take humidity at all. It is a base foliage plant which would have to be grown from seed and it might be difficult to get seed that is guaranteed to be named correctly since it has close relatives. Flowers are in spikes and are white.
Salvia microstegia comes from Turkey, Lebanon etc. Turkish salvias are frequently difficult to duplicate their preferred conditions or they may be very short lived.
Oils of salvia microstegia have antimicrobial and antioxidant properties.