I have 3 potted Plumerias from years ago Hawaii cutting. I’m in Kentucky, bring the pots in for winter. Had die-back more severely than ever, now have healthy looking trunk only, and of course many roots in pots (about 24″ pot) No growth happening. Do I fertilize and hope, or cut back again? One is down to a 6″ stub over the soil.
It is best to just leave them alone and see if they start growing on their own again. The exception is that if there are an rotten parts, you should cut them off plus another inch or so. Wait to fertilize until you see new growth emerging. If they haven't put out any growth in another month or so, then you can cut them back.