Hi, Dave.
Question - Which of these should I use? Would I be incorrect in thinking they are one and the same? I have photos to add to this plant, but I don't know the particular cultivar name for it, it just says "White".
Japanese Dogwood (Cornus kousa chinensis)
Korean Dogwood (Cornus kousa var. chinensis)
(Cornus kousa subsp. chinensis)
...and as for the primary common name; isn't this plant actually a Chinese dogwood?