According to the internet, it should be. We all know what that means though. lol. I have no direct experience with them, but would be interested to find out, they're on my list of plants to try to find.

Another fragrant flowering shrub that is evergreen in our climate that can handle some sun is the Mexican Mock Orange. I picked one up at Flower World (if you're in the north/east of Seattle area) that I'm absolutely smitten with. I'm getting a second set of flowers currently, and it smells heavenly.

this last winter in Portland the Ceanothus thrysiflorus in my neighborhood survived but looked a little sad. the mexican mock oranges didn't even blink- they were among the best looking evergreens thru jan/feb till the other ones recovered.

Yes, it is evergreen. Ceanothus thrysiflorus is a common enough plant in this area and is most noticeable in late May or June when it is in bloom. And it is much hardier than often given credit for as long as it has good drainage, rather lean soil and is pretty much left alone after establishment with regards to watering or fertilizing - i.e., don't! It has been discussed often enough on this forum so you might want to explore the archives for previous threads. And you might want know it is not a 'lilac' but ony carries that as part of its common name - flowers are held in small clusters, an intense blue and carry no discernable scent.

Looking for Mexican mock orange could result in a lot of confusion, as that name is more often applied to Philadelphus mexicanus (and sometimes Philadelphus karwinskyanus). Choisya ternata is most just often called simply 'Mexican orange'.

I know of a handful of pure Ceanothus thrysiflorus in Seattle. One is a hugely widely example in the native shrub groupings south of the Center for Urban Horticulture. I have not looked at it since this last rather punitive winter. One I planted on Camano Island got bent down and a little scorched. The tallest one I have seen here grew in the Vashon Island display garden of Colvos Creek nursery (on Maury Island). The property where the garden was located changed hands and is no longer open to visitors, so I do not know the current condition of the shrub.

The frequently sold and planted 'Victoria' (probably correctly 'Skylark') has hybrid characteristics, should never have been listed as C. thrysiflorus 'Victoria'.

There is a table of Ceanothus in the Sunset Western Garden Book and a recent Timber Press book on the genus. The latter gives specific minimum temperatures for multiple garden selections, that can be used to judge their potential on a particular site. Many are not all that hardy, making this the most important limiting factor at this latitude. Wild species not originating in gardens and having shown greater tolerance of garden conditions (including summer irrigation) may also be highly susceptible to dampness of the soil during summer, even when otherwise quite hardy to cold (a small number of species are native even in the colder winters east of the Cascade Mountains).

We live about 30 mile north of Seattle, and have Ceanothus in our yard. It stays evergreen, and blooms beautifully. Many of our neighbors use it also. It even did very well during the snows winter before last when many plants died. Ours came from a local nursery that, as I remember, got them from Monrovia.