i would not use a plastic bag cover. not sure which part of zone 8b you are in, but this time of year in direct sun would prob cook your cutting. might also promote mold/mildew growth.

i keep my cuttings under the porch in the shade for the first few weeks till they start showing some leaflets. water lightly then move them to the edge of the porch where they get a few hours of direct sunlight. then move them out to full sun after a few more weeks.

I got some huge cuttings from treasure island & one had flower buds, now after 3 weeks the flowers are opening up, now what about that ! I also got a load of seeds from thailand which are growing good toooooo, looks like the sun room is going to be full this winter, Frank in Old Town

Frank- If your cutting is rooting and producing flowers but not leaves, cut off the inflo. In my experience, flowers without leaves ends up an unrooted cutting. It is hard to cut an inflo, but the plant has a chance of rooting without the loss of energy to flowers. Also, my experience involves hundreds of rootings.

ok sounds good I ended up having to take the heat pad off because it malfunctioned and started to melt. good thing i caught if fast. I've also heard that they root better if left in the dark? anyone tried light and dark?

Not sure what you mean by 'plastic bag method'. I would never enclose a plumeria cutting in a plastic bag. It holds too much moisture in. Think about it like you're rooting a cactus. Lots of air circulation. Very porous rooting mix.

Perlite, pumice, fir bark mix might be a good mix.

Or 75% perlite and 25% cactus mix as long as it's kept fairly dry until leaves form.

I think rooting them with light is probably better. You want them to take off once leaves form. Now is the ideal time to root cuttings. But depending on where you live and how hot it is, some sun may be beneficial, while too much sun could burn them.