I not sure why you say you would not ever do a panorama on a moving object. Wether its vertical or horizontal don't understand why you think they should be shot different. Its much hard to get perfect reference for shooting stitching on vert pano. Which part are you saying is moving. The water or the dogwood.
My fear with moving objects is that stitching the photographs later may become painful: if some object that was near the edge in one photograph changes position before I make the next one; then I have to manually mask certain areas, or use extensive cloning, or... . I have a panorama made at Vienna where the same couple appears twice.
In this particular case, I was talking about the water, but now that I think about it, the effect of the long exposure on the water probably minimizes this issue.
Glad you like it, I tried to shoot it like Japanese silk screen. Tim
I like it, but I prefer the last one...