I can't think of a multi-season blooming California shrub. A bottlebrush of some sort, maybe? Oleander? Hibiscus? I'm surprised that you had trouble with bougainvillea roots, they're usually not a problem. Calliandra eriophylla, fairy duster, is a native, but not very flashy.

An oleander is probably the closest I can think of in terms of showiness, but it won't even come close to a bougainvillea. The flower clusters are not as dense, and you'll see a lot of green, unlike the mass of color possible with a bougainvillea. Also, oleander won't start to bloom until about this time of year, whereas bougainvillea can have blooms virtually year-round if you don't get frost.

Have you considered roses? Iceberg roses can bloom from Spring to Fall and would fit within your 5x5 size requirement. Some salvias could fit the bill too, though, they don't tend to be showy from a distance (only up close).

I'm surprised also that you would have foundation issues with bougainvillea roots. I've never heard of that happening.

To be clearer - I don't need it to be native - it can be from S. Africa, Australia etc. Given that, any suggestions?

All the other plants are native, but for this one, I just want to make my husband happy.

And with respect to the bougainvillea roots, the plant was a monster and planted right on the corner of the house...

Showy, non-native, drought tolerant?
Gotta go with an Aussie.

http://www.australianplants.com/

Grevillea. Not sure about any rebloom but it holds its flowers for a very long time. Mine has been in bloom since last spring. Coloring may not be exactly to your liking - yellow and orange tend to be the predominate colors but there are red and magenta selections available. Comes in a range of sizes so look for the compact or dwarf varieties.

We see mainly red Grevillea down here in SoCal.

Thanks for the great suggestions!

Chinese fringe flower - Loropetalum. Lots of varieites in various shades of red and purple, including many that will top out at about 5 feet tall. Drought tolerant when established.

For not so drought tolerant there is always Hibiscus.

Grevillea 'Superb' is very nice and the hummingbirds love it. Cordyline 'Festival Grass' is pretty distinctive in the landscape:

Wow, learned a lot from this post. Nils, I love Hibiscus , so pretty, are there ones that are slightly more drought tolerant than others?

Of the tropical Hibiscus -rosa-sinensis,the more it looks like the traditional red,the hardier and less water needy it will be. The big leafed and flowered evergreen kaleidoscope colored Hibiscus are not up to frost or drought.

Maybe the original boug was planted too close to the house and the problem was really the size of the trunk? You could plant a new one a foot further away from the wall for that long season of color.

Jxbrown, that is probably the case, it was right on the corner of the house. I am actually lukewarm on boug, lovely color but requires lots of cutting of thorn-ridden branches to stay under control. I think that it is a pass for me, as I want to plant bushes that stay the right size (file under life is too short).

There are some smaller cultivars of bougainvillea, not all of them are monsters. 'Rosenka' stays pretty small. Another one that is supposed to stay smaller is 'La Jolla' I have personal experience with the former and I'll see about the latter as I just planted one at my mom's house.

I think you should consider a large perennial. Some Salvias get to the size of shrubs. Then there is Leucophyllum frutescense

Perovskia atriplicifolia is also impressive. It can get large but there is a small version too.

Thank you everyone - especially Nil13, I went with a Bonfire Grevillea which will eventually be just the right size (about 5-6 ft).

In the future, check Annie's Annuals. They have lots of stuff that would meet your criteria. Annie's Annuals and Perennials