Definitely out of range in Ottawa, which would be USDA zone 4 (Canadian zone 5) I think. I'm a little west and certainly USDA zone 4 but I'm not sure if the city heat island effect is taken into consideration there. Apparently there are also a few tulip trees in Quebec.
I've seen the one in the Ottawa arboretum but not in flower. How does our phenology compare right now - the common golden leaved mock orange is in flower here, lilacs mostly finished, black locusts probably almost done?
