Well it all depends on which you prefer, sambacs or other jasmines. Sambacs, I'd say a maid of orleans to wind around the obelisk, otherwise possibly the volubile or maybe just a plain old officinale. I take it you wouldn't want something which smells like jasmine but isn't? You may want to consider mandevilla laxa, it grows like crazy and smells of jasmine or as it's known (chilean jasmine). Would be quicker to vine around that obelisk than a sambac and is far less fussy to grow.

J. Sambac is more of a lax woody shrub than a vine -- it does not have the best habit for an obelisk.

Other good, fast fragrant growers include j. azoricum, angulare, nitidum, and tortuosum (humile and odoratissimum, too, if you like yellows)

Don't forget other "non-jasminum jasmines" like trachelospermum asiaticum and jasminoides -- I know you want a true jasmine, but the fragrance of these is just as good as the real thing!

Jim

The azoricum, humile aren't that fragrant if at all. The trachelospermums would vine but would take a very long time, I'm still of the opinion that a mandevilla laxa is the best option in this case, it's also hardyish and really is a rampant viner with fantastically scented flowers.

RisingPower, my J. humile "Revolutum" from Logee's has very fragrant yellow flowers, but it is not really a vine. It's more of a large spreading shrub.

I had an azoricum, and while it wasn't my favorite jasmine fragrance, it was definitely scented and a fast climber -- just goes to show different plants and different noses will tell you different things!

Yes, the trachs, especially asiaticum, can be slower growers, but the plant habit is neater than a lot of true jasmines, IMHO.

Jim

Hm maybe I just wasn't able to detect the scent on the humile or azoricum, I know I definitely couldn't smell much with the azoricum when I saw it in a conservatory/greenhouse area. The only one which I remember smelling was the grandiflorum de grasse, tried the standard sambac, and whilst it was fragrant, nothing like as strong as the grandiflorum and I think the grandiflorum actually smelt better. The trachelospermums some people love, some people hate, personally I think they're fantastic for the UK, a hardy jasmine that flowers profusely around here.

Do have most of the "non-jasmine jasmines" you mentioned, and I agree they're very nice! Hard to explain, but the trellis design is such that a jasmine won't be as plain as it sounds.

Also have 'Maid of O,' and it definitely would not work on a support. It's quite shrubby as Jim said.

Your comments helped me narrow down to tortuosum and officinale, but Tovah Martin makes the latter sound pretty finicky. Sounds like it may be worth the risk, though?! Thanks so much for your help!

You have the mandevilla laxa then I take it? Officinale is fragrant, but not nearly as much as the volubile, tortuosum or nitidum. There's a grandiflorum de grasse variety of the officinale which smells fantastic though.