Until the blooms appeared, I thought this was another salvia transylvanica.
It may still be. Salvia transsylvanica is a relative of S. pratensis, which fairly often throws white (alba) and rose (rubescens) forms.
Ah, so it is probably salvia transylvanica after all! Will seeds from this plant revert back to the blue flowered variety, or will they produce plants with white flowers? I have a couple more transylvanicas that are getting ready to bloom, so it will be interesting to see what color flowers they have.
Instead of a 1:200 ratio of producing an off-color, the odds may be reduced to, say, 1:15. You need to isolate the plant from possible cross-pollinators by about 1/2 mile or so to really improve the odds.
Ha! I could move it anywhere else in Newport News and it probably wouldn't get pollinated, but I have at least 4 transylvanicas in my yard. Oh, well. I'm not going to dig it up.