I've been experimenting with various cuttings taken during the winter (so hardwood cuttings). I've had some failures: taking from plants that (I now know) don't propagate well from hardwood cuttings, or simply having <100% success rate with cuttings that 'should' work. I also had some encouraging successes.
One thing I'm uncertain about is how to store cuttings, if that's possible at all. So far I gather the cuttings I take in a bundle wrapped in a damp cloth, then bring that in a dark cool place to overwinter until I'm ready to stick them in pots or in the ground. Since they seem inert, I don't water them at all, but I notice that by the time I revisit the stems and cut them to appropriate sizes to be stuck in soil, the cloth and stems are both pretty dry. As noted, some have worked, some have not, so I'm unsure of how good or bad this method is.
So, how can I store hardwood cuttings, if at all? Should I be watering these inert cuttings over winter, and if so at what pace or moisture level do I want to keep them? Should I put them in the freezer wrapped in a damp cloth or dry cloth? I've heard of sticking them in buckets of slightly wet sand and keeping that sand slightly wet and in a cool dark place over winter but haven't tried that yet. Does storage depend a lot on the species or are there general rules of thumb for all hardwood cuttings?