Hey there Nigella,
Have you tried a rooting hormone? and what types of media are you using to root these plants?

Nigella, I can tell you that Rosa Mutabilis is difficult to root, but not impossible.

I use peat/perlite- 50/50 mix and I like it nice and damp.

I use Dip 'N Grow liquid hormone, and mix it to the 10x dilution rate.

8"- 12" long cuttings, I like to have a couple of nodes in the rooting medium. I scrape my cutting between nodes a couple of times, to wound the cutting.

Let the cutting sit in the Dip 'N Grow for a few seconds up to a minute, then stick as you would anything else.

Set the pot in a shady spot of your greenhouse, and don't let the rooting medium dry out. If you have a misting system, that is great, if not, just be sure to not let it dry out.

This is one that you should stick 20 (or more) at a time, to get 'some' rooted cuttings. Not the most difficult, just not easy. I think a lot of it is 'Luck'.

I have never had any trouble with clerodendrum. I do them in much the same manner.

Good luck.

Janie

I tried airlayering the clero. One worked and after two months, it is still recovering after an additional two months.