Have had this beautiful little violet for years. V. o. Sulphurea blooms occasionally and poorly, and the plants, themselves, are uncommon. I can recognize a distinctive nature to the leaves of this plant, as blooms come so seldom.
Where a common violet, I call V.odorata, grows like a weed, everywhere, and the white form is hardly rare.
And V. sororia 'Freckles' is even more like a weed than any. Zone 7A, acid, sandy soil.