I would keep pawpaw in slight shade. Pawpaw are sensitive when it comes to transplanting, especially when that large. Wow, 5ft? how long are those roots? Pawpaws have a long tap root, so the container needs to be deep. They do fine in the sun in the ground, but keeping a consistent moisture level in a container in full sun maybe more difficult.

The Container I bought was the biggest one I seen at the Store about 3 Ft tall and the tap root is about 6" from the bottom so next spring needs something a bit bigger for sure. I bought two trees the 5ft is a Seedling from a Davis Cultivar but not sure if it will be any good also bought a grafted NC-1 but its only 3 Ft right now. I agree the moisture will be an issue thats why im thinking of maybe digging a hole in the yard and burying the containers.