Transplanting pawpaw trees is difficult. Pawpaws have a deep taproot, and great care must be taken to prevent damage to it and to the rest of the root system. Dig as deep as possible, and keep the root ball intact. After transplanting, prune top growth in proportion with the remaining root mass (i.e., if one-third of the root system was lost or damaged, trim off about one-third of the top growth so the remaining roots will be able to support the tree).
Root suckers often don't have enough of a root system to support themselves. You can try to encourage development of an independent root system by cutting partway through the connection with the mother tree some weeks prior to transplanting.
