@Thomas75 I've never had any luck rooting muscadine cuttings or grafting any. I've rooted some vitis hybrids cuttings this year and successfully grafted several vitis vinifera on on 3309C and 101-14 rootstocks. I find muscadines are easier to layer than root or graft. Did you use dormant cuttings or cuttings from actively growing vines? All my cuttings I've tried have been dormant cuttings and quickly die after leafing out. I've tried cuttings placed in high humidity and without. I've tried them in potting soil, just sand, and just perlite but nothing has worked. I've also tried both gel and powder rooting hormone and still no results. I gave up on rooting them because of the aggravation but layering the plants are a breeze. just lay a vine on the ground and cover with potting soil then cover that with mulch in a few months you'll have tons of roots. and can just come in and snip them off and have new plants for your garden.
I also trade a bunch of plant material every winter. Do you know how to graft? If you ever want to swap some scion wood or cuttings of named plants please let me know. I'm good on muscadines but would love to hear what else you grow. Feel free to tree mail if you are interested in working something out this winter. I have a list of everything I grow and would be happy to share that with you.
