I have many Sweet Olive in my yard; I would not be without them. One of my top 10 plants I recommend to everyone who will stop to listen to me! Mine are about 15 ft. after 9 years. As a transplant from the North also, I missed Lilacs too. Once I smelled Sweet Olive (and Gardenia!) I forgot all about Iowa, lol. At the garden center I work at, I once asked all the employees to put a name to the fragrance of Sweet Olive. We all stood there, inhaling the amazing fragrance, trying desperately to come up with a description of the smell. Finally, one lady came up with it...get this... it is a mix of sweet cream, vanilla and canned Apricots! THATS IT! Next time you are smelling it, think about that description- it works!
Mine, here in Texas, bloom 2X a year- spring and fall. They are day-length triggered.