Hi, I haven't taken cuttings of this particular plant, but as they're suckering plants, you have a choice, you can either take greenwood cuttings in summer, or use rooted suckers in autumn or spring, Derek.

I haven't taken cuttings from Diablo but have successfully taken from Lady in Red and Nugget.
I didn't do anything technical - just popped a couple of stems into some gritty compost, mid summer if I remember correctly - then left them to their own devices til the following year. They must take quite easy if I can do them Sheila :)

Thank you Derek and Angie. I took eight cuttings today: four with rooting powder and four without. I've just watched Monty putting a plastic bag over his (which I haven't done) but I can see that I should attempt to keep them 'misted' (and presumably somewhere cool).

I've not tried cuttings, but I get a few self-sown seedlings each year. They seems to come true as well. I also have Dart's Gold, but I'm lucky if I get one seedling from that.

I kept mine in a corner down the side of the kitchen step, which would have kept them cool. I certainly gave them no protection in winter as I've no where to do this.
The misting and plastic bag are obviously for technical reasons I've yet to learn ;)