Maine is abloom with lilacs everywhere you go in May...lots from old farm-sights with buildings long gone.
I lived in Calif for a few years and saw exactly ONE lilac and One birch tree.
The lilac was on the fence of an old cemetery from the 1800’s. I imagined it being lovingly wagon-trained all the way from New England, only to have the lady in question die before or as she got to Calif. and someone, probably husband, planting her lilac there where he buried her.
Since it was still there after all the decades (This was 35 years ago) I would say they grow ‘if they're planted”
Ditto birch trees. Never saw a white birch in Calif - until I planted one in my front yard - 35 years ago. People would stop and ring my doorbell to ask “What kind of tree is that?”
Today, the tree is still there.
I'd say, give it a shot. Whadda ya got to lose?
My grandmother had a lilac tree that bloomed and flourished alongside the shed in back of her house in Fresno when I was growing up. However, it was really puny compared to the lilacs we have in Wisconsin. But, it survived for many years with little care. It might still be there, for all I know. It was a purple variety, but some people in the neighborhood grew white ones, as I remember.
I think that lilacs need really cold weather to flourish, and the Central Valley of CA regularly posts temps in the 20s overnight for a few weeks in the winter. That’s when the farmers get the smudge pots out for the grapes and the citrus orchards. It’s enough cold for the lilacs, but they won’t ever get as big as the mid-western varieties.