How can I preserve rose clippings until it's time to plant them?

How can I preserve rose clippings (and those of other propagating plants) until their planting season?
I have several rose clippings at the moment. some from before the past winter (-20) which I have dipped in water until now. Some others just laying around in the garden awaiting their fate. The soaked ones are not rotten (yet).
All are in good condition. various sizes.
I’m just at, say, my second stage of the rose cultivation science.

HELP! (cries the crowd of thorny green stems)