Back in early January I decided to try my friend Simon Voorwinde's technique for rooting hardwood cuttings of roses. This technique could prove useful for cultivars that might otherwise be difficult to propagate by softwood methods. This is Simon's technique:
"All you do is make all your cuttings somewhere around 15-20cm long (I cut the base with a sloping cut behind a bud), remove all their leaves as they harbor lots of fungi etc (you could dip them in some kind of fungicide but I don't tend to bother), bundle them up and wrap them in newspaper, put a rubber band around the top and bottom to keep the whole thing together. Run the newspaper under a tap to moisten it, allow all excess to drip off, then seal it all in a plastic bag and forget it for a while. Some will begin callousing after only a week.
When they've started callousing pot them on as you would normal rooted cuttings and keeping them humid until leaves and roots begin to appear. I have a few large clear tubs (about 140 litrres so nearly about 70cm long by 50cm wide and about 40cm tall) that I put a 10cm layer of moist perlite and peat in that I plant the calloused cuttings straight into, put the clear lid on it, put it outside in a shaded position (as the sun will cook them quickly) and they are ready to begin hardening off in just a few more weeks. With my multiflora cuttings I do this except instead of planting them in the tub I stick them straight in the ground after pre-callousing them and they are away in about a week and I tend to do about 50 at a time. I do this at all times of the year and it occurs faster in the warmer months than the cold."
The photo illustrates my results with one of the Kim Rupert Gallica hybrids I use in breeding. Cuttings were taken from a fully dormant plant and placed on top of my fridge for about 6 weeks. As you can see these calloused easily and have roots well formed, ready to pot up. I would suggest experimenting to find the ideal stage for potting these up; some varieties might work best if potted before roots formed and others might fare better with roots well on their way.