Dave is right - the flowers size of this one is typical of the species. But the rub is that very few true S. greggii varieties are in cultivation. The vast majority have some S. microphylla genetics in them. The range of these two overlap, and both in the wild and in cultivation they cross promiscuously. So many of the plants that are offered as S. greggii are actually S. x jamensis, the name of the hybrids having S. greggii and S. microphylla in their background.
Why is this? Well for one S. greggii in general are far more cold hardy than S. microphylla. So companies like Ball who released and promoted Salvia greggii 'Radio Red', which is actually a S. x jamensis and not a S. greggii, I suppose to influence customer perception of the degree of hardiness. In many cases the party who develops / sells one of these is not aware of this distinction. So the naming gets more and more confused.
We believe Teresa is a true Salvia greggii.