Salvia leucocephala is a spectacular new arrival since 2020. I suspect it has been made available through a plant specialist in Argentina, Rolando Uria, who sells seed of exotic South American salvia species.
Flowered for me in July 2021 (winter). Watching the white buds for weeks heightened anticipation. It was about 50cm in a pot at the time so I could move it away from frost but I imagine it might grow to 2m. It is not very frost tender but I haven’t tested it enough (2021). It is evergreen. Cuttings are easy.
As at June 2022 orders are outstripping ready plants so they are out of stock for a few weeks. Since it is cloudy and rainy they don’t grow quickly. The lack of a lot of sun is making the foliage green. (Drought makes foliage whiter.)