At last, a perennial salvia that attracts hummingbirds. (The other perennial salvia in our yard that hummingbirds go to is Salvia glutinosa.) Salvia azurea is reliably hardy in our zone 5 garden. It blooms late in the season which is the time that we have the most hummingbirds in our yard. It is approximately 4 feet tall and requires support to keep from falling over. But, it is well worth it, as the hummingbirds use this to a moderate degree.
Our plant died out, as it prefers dry sandy soil. This plant is not easy to find. The following sources have Salvia azurea: