I didn't even know what you were talking about, I actually thought you were talking about the type of plants you can buy at Walmart or Sam's (just the only two sources I knew of ) a little dried up plant with some roots and a crown with a little peat moss thrown in with it.
But this article talks about rhizomatous hostas.
http://www.hostalibrary.org/sp...
So it looks like to me the rhizomes should have been spread out instead of being bunched up and planted vertically. Then the roots should form from the rhizomes and spread down and the eyes would emerge with the leafs spread over a larger area?
This is the best link I could find with info on them, it includes some suggestions on how to plant them.
https://ask.extension.org/ques...
Hope this helps.