Today I've been able to smell Rosa sicula in the Botanical Garden of Meise, Belgium. So I'm giving some notes on the smell, now they are still in my memory. I've rubbed some young shoots and smelled them up close. The type of smell is akin to that of a Rosa rubiginosa, but still different. You have a smell of apple, but with something more earthy, sweet, maybe spicy.

As to strength of smell. I did not smell it from a distance, but this was a single bush. Not yet very large (about a man high). It is september already and the conditions maybe weren't entirely ideal to carry the smell far. In the garden however there were some large Rosa rubiginosa and they did smell from a distance.