Phlox subulata ‘Amazing Grace’ is a cultivar of Phlox subulata ssp. subulata (see that entry). The flowers of ‘Amazing Grace’ are bright white with the tiny golden exserted stamens closely surrounded by small maroon markings (nectar guides) at the base of the petal lobes. The USDA plant distribution map linked below is for Phlox subulata ssp. subulata.