Forget armandii - you are much too cold in Buffalo for that species and you are even pretty iffy for any montana. If Betty Corning has any scent it is so faint as to be almost nonexistent. I have never seen xaromatica for sale by any US vendor so can't comment on that.

But triternata Rubromarginata is a good choice...as is the closely related Sweet Summer Love.

@gardengal48 (PNW Z8/9) thanks, i forgot to take armandii off the list. too cold here for that one!, the mayleen says zone 5-10 or 6-10 so i think im good for that one, have you smelled it? if so- which is more fragrant, that or rubromarginata?

Armandii is the most fragrant, hands down. And in colder zones a montana like Mayleen may seldom if ever flower because the oldest growth - what will produce any flowers - is cut back by winter cold or late spring frosts. And montanas are definitely a z6 vine....more like z6b.

A summer flowering (new growth) clematis like Rubromarginata will work better for you and the scent will be more discernable in the heat of summer as well.

Aside from armandii, none of these produce a very heavy fragrance. A light, honey-almond scent that is pleasant when you get a whiff but neve cloying or overwhelming. They are not going to scent the entire garden.