Border of 7B/8A U.S.A. ...flowers before leaves.
I am sorry that I could not get closer. It was surrounded by a fence and a menacing thicket of thorny nastiness! The blooms looked to be about 5cm across.
SOLVED: Lovely Large White Blooms on Tree
Paulownia tomentosa. Normally the flowers are a light purple color but they can be white.
Hello from the looks of the flowers you may have a Pawlonia fortunei thatís where I would start we saw these growing in China during some trips they are striking when in full bloom