Geranium Rozanne.

Yes, awesome plant, 'Rozanne'. I have a dozen of them at least. Needs a good amount of, and attentive watering to get established--vulnerable when first planted. Best planted in October or later. Too hot now. That goes for just about any plant right now, I guess.

A nice low-water low growing plant is Hairy Canary Clover, Dorycnium hirsutum. Low (but not zero) water needs

Pyrethropsis hosmariense aka Rhodanthemum hosmariense , aka Morocco Daisy, tough little low plant, long-lived, mine is 15 years old and still going strong.

Solanum xanti, tough low plant, a lower water CA native sub for 'Rozanne'.

Erigonum grande rubescens, lovely lovely CA native, I keep killing it for some reason, maybe not enough water.

Calylophus--tough and low water, but needs regular water to get established. Blackfoot Daisy--Melampodium leucanthum.

Well that is what comes to mind offhand. There are always annuals if you just want something temporary.

Thanks to you both. The hardy geranium would work well. Hoovb , " comes to mind offhand". ?! Lots of knowledge stored there! Are these things that Green Thumb or PlantDepot would stock? How about this idea for cheapskate, fast (?) solution: transplant these African Daisies that have grown too much and too large. Doable, and can their height be kept to 2-3 feet? I have a long bed to cover, and these are free :). Getting ready to thin them out , anyway. They are so easy to pull out, but to transplant?

FYI. My plan is to keep the new plumbago trimmed to bush shape , while existing will be kept as a trailing vine.

Funny about the microclimates, isn't it? I have never been able to grow Erigonum grande rubescens, until this yard, that is. Now I just dig up seedlings willy-nilly and plop them into holes as filler, water them once and they're good to go. They have just started to rebloom after their July haircut. Hard not to fall for that watermelon pink.

I love that Erigonum. It's simply beautiful. I just want to not kill it again.

Sure, you can move those Osteospermums. A great plant, but they need rejuvenation pretty regularly. Every few years. Very few people ever do that, so they end up looking ratty.

By rejuvenation, I assume you mean pulling up every other plant and cutting back the rest. Mine are sooo prolific they need it yearly, or more! . At least they do cone out easily. I'm going to look for erigonum.