ARS states that the blooms have a diameter of 4-5 cm. Someone must have mixed up centimeters and inches. On photos with foliage, the blooms do seem smaller than 10 cm. Someone who grows this rose might have first-hand experience.
In 110 heat index, she is covered in blooms with a strong fragrance. In afternoon sun, the color does bleach to a dirty white but they are long lasting blooms, both on the bush and in the vase. The size of the blooms are three inches, sometimes a little bigger. This is comparable now to other varieties which normally have bigger blooms but get smaller in high heat. Own root, sandy soil with alfalfa compost.