These are called bushes, and yet they can easily get 20ft. tall.
Fremontodendron “Pacific Sunset”
Fremontodendron “San Gabriel”
Fremontodendron “California Glory”
I don’t know if there’s a whole lot of difference here. Some slight variations in flower color and leaf shape. But these are all in the 10-20ft. tall range. “Pacific Sunset” is maybe the tallest of the 3 and can get over 20ft. on a good day.
Plant them out of the way of pedestrian traffic since they can cause a reaction if you rub them the wrong way.