Shhhhhhhhhhhhhhhhhhhhhhhh!
What I'm going to tell you is a deeply guarded secret in the ag world

The University of Minnesota developed a marshmallow tree in the early 60's, but the medical and dental field at the U squelched it. However, it is still being raised in a far back corner of the arboretum at Chaska, and it is cataloged for sale as
Sta Puft Hybrid #2462 - suitable for growing zones 2 - 6.