I have this D mexicana vining away about to touch the ceiling 7 feet up. Not one leaf on it. When I repotted it several months ago, I filled it mostly with drain rock then a pumice and potting soil based mix, and recently took the rock from the top and used my standard mix to the top of the rim of the caudex. The plant gets morning sun, but no more. Right now the trellis is hanging from the curtain rod, and not attached to the pot, making moving interesting. Not to mention the pot is about !00#.
Is this normal that leaves come later, or do I need to do something different?
I am a big fan of that site, but there is no mention of them being vine first leaves later. And as far as winter grower, have you seen his post on other Diasocoria, as they don't have a very good time table. just water when growing.
The leaves will be coming. Patience is necessary. I grow a couple of different Dioscorea and it is not uncommon for them to send up long, leafless shoots like your plant has. Then later the leaves will arrive.