Ok, if you grow old roses you might know the answer to this. (cross out Lady Banks and Father Hugo, because unfortunately they haven’t made it into the collection).
The first rose to tease with a cracked open bud was Christopher Marlowe, a bold orange/red/yellow Austin rose with a great tea perfume. Then Evelyn popped open her sepals, then the luxurious Mme Isaac, Sombreuil, and Munstead Wood. But something about very fully double roses means they take a long time to open all the way up at the beginning of the season.
While those quartered roses were languorously unveiling themselves over a couple weeks two old roses came in from behind like my bro Jo Buffo the bunny rolling up on a turtle. Jaune Desprez, a slightly quartered apricot noisette dropped its sepals overnight, and if I remember correctly it was the first to bloom last year. But today the petals have yet to separate.
Which leaves the winner, as in most years, just according to the textbook: Old Blush. The individual flowers are not spectacular, but the smell is pleasant, some say like sweet peas. I’d say Old Blush has a little bit of the scent of a bourbon rose. When the bush is in full bloom it is a beautiful plant. Right now three small blooms is plenty after a long winter.