I first saw this in the late Alan Bloom’s garden in the UK a good 30 years ago. From memory it was about 3.5 metres tall and 2 metres or so across; the whole smothered with pure white flowers like exquisite single roses. I didn’t think any more about it until a friend gave me a plant a few years ago. We have it planted near the house in a garden that gets watered occasionally during the summer. It has reached 2 metres in height. Best in sun or very light shade.