There are literally hundreds of possibilities. There are also a lot of different climates in the Bay Area so you'll have to be more specific as some of these are tender to frost while others need some heat. "Grows with little maintenance" means different things to different people. Many of the vines that grow with little human intervention grow with abandon and may need periodic pruning to keep them in check. Some vines are deciduous and shed their leaves while many others are evergreen (and still shed leaves, just not all at one time).

A few of the major groups would be passifloras, solanums, clematis, tropaeolums, thumbergias, bougainvilleas, ipomoeas, mandevillas, bignoniaceous vines, grapes and parthenocissus. Several honeysuckles and jasmines have no scent and have white, pink or yellow blooms. There are many one-off genera like Lapageria, Sollya, Hoelboellia and Rhodochiton that also include good subjects. If she has a warm sheltered spot, she may be able to get away with growing Petrea, which has beautiful purple star-shaped flowers.

There are also a lot of climbing plants that aren't really vines including climbing hydrangea and many roses. How do you want to narrow down this vast field of candidates?

Sorry, I don't actually live in the area, but I believe the area is Walnut Creek, which means the temperature range is hotter and colder than say San Francisco. Hardiness zone is listed as 9a-10a. I believe it sometimes snow there, but it is rare.

Her patio is surrounded a wooden "wall" that look like sticks, you can see through it. She wants to increase privacy by covering it with some of vine, but HOA rules indicate that nothing can be attached to the wall. One idea is to setup planter boxes with caster wheels and attach trellis. The plant should also grow in a fairly narrow planter since space is a premium.

I suggested that she grows some bamboo since it requires no trellis but she hates bamboo. She wants some sort of vine that is fairly maintenance free and have flowers that bloom for long periods of time but does not have a strong scent. She also indicated that she wants to avoid the color red because it's not a relaxing color. Apparently, she does not like ivy either. Maintenance free means it should grow without taking up too much time other than periodical pruning.

Hmm.. I was under the impression that most leaves on plants don't fall off in the winter, but I don't live there and may be wrong.

Paul

If the container is big enough and she is willing to keep it in control and consume a strong enough trellis, passion vine Passiflora might work, depending on exposure.

Dan

It can take over fast so it will need pruning, but I put "potato vine" on one side of my garden. I think the botanical name is Solanum jasminoide.

It is evergreen and virtually scent free (I can't handle those strongly-scented vines either). My hedge clipper keeps it in check, but it is fast growing and extremely hardy.

What about Bignonia capreolata 'Dragon Lady'? Big red trumpet flowers, does well in heat and cold, no scent, very, very lovely. We have planted this in our development along our black metal fences and it is doing very well. We are in a similar zone (9B to 10a) with some cold temps in the winter and it has survived very well for us.

Patty S.

No plant is maintenance free. The fact that the plant will be growing in a container rather than in the ground takes it out of the low maintenance class as well. Containerized plants are more dependent on human intervention for their basic needs than those planted in the ground. Planter boxes with attached trellises are highly prone to blow over because of the big sail you are making for the wind to push against. You will also need a vine that will be happy with a limited root run. Many vines also produce delicate tracery rather than a solid concealing wall of foliage.
Your sister's hypersensitivity to floral fragrance also eliminates any plants that are bee or moth pollinated (many if not most). There are a number of hummingbird-pollinated vines that will not have fragrance, but many of them have red flowers (that's what attracts hummingbirds). Some possible prospects are:

Ipomoea quamoclit 'White' (White Cypress Vine): This is a hummingbird-pollinated vine that is normally red-flowered, but comes in white if you look for it. The foliage is also highly attractive when it is not in bloom.

Bomarea salsilla: A vining bulb from Chile with bright pink flowers of a calming hue.

Pandorea pandorana (Wonga-wonga vine): A bignoniaceous vine with white or golden flowers that is reasonably dense without being overly vigorous.

Clematis 'Venosa Violacea": Just one of many clematis varieties. Most of these are deciduous and will be only seasonal in their foliage coverage. Deciduous plants lose their foliage even in milder climates. It's a trait that runs in the DNA.

Tropaeolum tuberosum 'Ken Anslet': Another hummingbird-pollinated vine that is a good compromise between delicate growth and adequate coverage.

Solanum jasminoides or Solanum crispum (Blue or White Potato Vine). Already mentioned. Its vigor will either be restrained by the container, or its roots will break through it and creep into the ground. Will need pruning but it's tough and pretty and stays in bloom a long time. The blossoms don't have fragrance but the foliage will smell somewhat like a tomato plant does at close range.

Believe it or not, seed-planted annual vines may be the best bet for lowest maintenance/fast establishment in this kind of situation. Dolichos lablab, annual morning glory, Mina lobata, nasturtium and cup-and-saucer vine (Cobaea) are a few of the possibilites here.

Were it I, I wouldn't do it. It doesn't sound like a good idea (neither does living in an HOA situation), and your sister sounds like she suffers from Princess-and-the-pea Syndrome and probably won't be happy with any outcome even after all the work that goes into achieving it. The obvious answer I suppose is for her to go to a nursery and pick something out herself after talking to the staff about what she wants.