Very large hostas are generally over 66" wide when full grown.
Size code legend:
TC+ A Tissue Culture plug that has been grown on for several months after
one dormancy and is now ready to be planted in the garden.
All other sizes have had at least two dormant periods, but usually more.
E A mature, one-eye division of a container-grown or field-grown plant
E2 A mature, two-eye division of a container-grown or field-grown plant
C Three or more eyes; enough to make a small clump
C2 Six or more eyes, enough to make two clumps
C3 Nine or more eyes, enough to make three clumps