Robin, David does cite an exception to your list - the Deut will be happy almost anywhere in your yard and would enjoy the winter rains. Just as some additional information, one thing I've noticed is that there are several, if not hundreds, of exceptions, but in general most pachycauls go dormant. Under the above-mentioned structure, of all my Adeniums the Adenium arabicum never lost its leaves (so I watered it in winter) and, oddly enough, the from-the-winter-rainfall-area Pachypodium namaquanum lost its leaves for the briefest amount of time of all my Pachys (I had around 11), so if it was in leaf I kept watering it, although in San Diego they were protected from the rains most of the time in the winter. Up here, my Fockea edulis, Raphionacme flanaganii and Jacaratia corumbensis do not go out of leaf in winter, so they get some water, though not as much as in summer, when they're outside and in full (shaded) sun. The rest of the usual suspects (Cyphostemmas and Burseras, with the odd Commiphora) go dormant wherever I've had them. But I'd agree with you - learn what you have and where it's from, and that will help a lot.

Ceanothus Joyce Coulter is a low-growing variety that could fill much of that square. Have you thought about going to Las Pilitas Nursery? I think it's in San Diego County. It may not be far from you. If nothing else, you could look at their website for pictures. They have lots of information about drought tolerant plants. I have never been there, but have gotten good info on the website.

Poppy cock I say to the liquidamber haters. Different strokes and all, but to me the beautiful fall folliage is every bit as breathtaking as any flowering tree. Yes, the balls are ouchy, so not recommended where one might go barefoot. Yes, the roots can show above ground, but not very noticeable except in the most pristine lawn. Our forty year old neighborhood also has many near the sidewalks and none are damaged at all by the roots. Not sure, but believe the rotundaioba are quite slim and look best planted in duplicates. You can keep your fabulla-tabula. :). I'll always love my LAmbdrs best! Below are my two and neighbors behind. They " bloom" from late Oct. Thru late December.

I think the question is "What plants might work here?" Some additional goals might be helpful - low maintenance? low water use? appealing flowers? flowers for cutting? prefer foliage? interested in a tapestry effect? If you are in a similar zone and growing conditions, you certainly can use the same plants. Or you can wander around areas where you like the plantings (nurseries with demo gardens, perhaps the San Diego zoo, any botanical gardens in the area, or homes with plantings you find appealing) and take photos of plants or arrangements you like. You can take the photos to nurseries or post on Name that Plant forum to get IDs. You may also find that asking this on your local area forum (southwestern or California) might be more useful as far as plant suggestions. Generally this forum deals with design questions rather than plant selection issues.