If you can find something that makes good roots (Multiflora, Fortuniana, etc., you might just be desparate enough to try stentlings.
The link below tells a lot.
Disclaimer: I’ve never done this although I know some exhibitors in the Carolinas who do this and at least one who went back to more conventional cleft grafting.
But desparation is a mother of invention. And with a mist system, and really well draining rooting medium…at least it’s an option.
Only “weed heads” eguate horticulture with weed. I’m sure the rest of the public thinks of flowers and shrubs. So all is not lost.
It’s too bad that the scions won’t root on their own.
Last year I rooted several R.blanda root cuttings(from suckers). I might work if the scion was grafted onto something like that. I also have R.blanda seedlings from last year, they would already have a root system to support the scion. Grafting onto one of those sounds the most promising to me.
“How unfortunate that I have no understock prepared at this point in the season”
I’ll be the first to admit that I know little about budding/grafting. However, if you need leftover rootstock from last year, I can help you on that. Due to a death in my family last year, I didn’t get a chance to use it. There is nothing wrong with it. It is still dormant, and it is destined for the compost pile.