Ceanothus, Ceanothus, Ceanothus...
Several varieties do better in the urban landscape than others of course, and since this is a native lilac, the watering schedule is hugely important.
Just because they are natives, you might think,"Oh they'll be fine in the car for a few days without water."
But alas, they die. I've killed my fair share of 5 gallon Ceanothus' because I was too lazy to take them out of the car and give them water, and too unorganized to put them in the ground after I bought them. They can be pricey for larger sizes, so best to plan ahead.
Ceanothus rule of thumb: the smaller the leaf, the slower the growth.