Your USDA zone???? A Sunset zone will be a lot more specific for California. Look that one up. Have you checked out your local nurseries to see if you can find those plants? Do neighbors grow them? That will be a clue regarding how well they will do in your area...not your zip code. Many micro climates here in CA, within one zipcode.

-Babka

USDA is 9b

Well so am I (USDA 9b) but I am down near San Jose and my weather is totally different from yours up North. Again, I suggest you take a good look around your neighborhood and see what is growing well, and also go to a local Nursery (not Big Box store) and ask them the same questions. A knowledgeable nurseryman will be able to tell you if those particular desired plants will do well in your area. And also please consider the location. Just about any plant can be happy with eastern exposure (morning sun). Some need all day sun, or at least 1/2 day. If the brick wall faces South and is white, your plants will cook because of reflected light. Good Luck!

-Babka

One option to look into is adding a wrought-iron topper to the wall and growing a vine on the wrought-iron. That keeps your screen very narrow and the root systems of most vines are less likely to damage a block wall than trees. A wrought iron topper on a block wall is usually legal but check your municipalities zoning laws.

Stick to medium to large-(ish) shrubs ("medium" is still quite tall, 15'+) rather than trees if all you need is screening. Most plant tags show size at 10 years of age; trees will continue to grow beyond their size at age 10 and may end up too large for your requirements.

If you are in the lowest elevations of that zip, Sunset 14; in the higher elevations is Sunset 8 or Sunset 9.

Fairly certain Little Gem Magnolia will grow nice here. I mentioned it to a landscaper that came by to do a quote and didn't balk or talk me out of that one. Might be easier to find than Jane Magnolia too.

Still need to get to the nursery but haven't had time. :(