Take cuttings of firm new growth apply 0.1% IBA (rooting hormone) stick in well drained soil & mist.
How can I know what you did wrong whenI do not know what you did

You didn't do anything wrong. I have been trying to root this plant for years. It is very difficult. Pat M.

They can be rooted successfully by ground layering. I have done so couple of times.The only draw back in this process is it requires about 10 to 12 months for layered branch to root.
This method has been described in Chap.4 of Secrets of Plant Propagation by Lewis Hill.You may do your own research for more info..

Chaman is right about the layering. It is the only way I have ever been successful in propagating this plant.

I have it growing on an arbor in dappled shade. I bought some of those hangers for pots that will hang on a fence, and I layer the vine in pots right on the arbor.

I nick the node just on the plant side, and give it a dusting of rooting hormone before laying it on the pot.

Being in a shady environment, this Rangoon creeper doesn't bloom much, but it sure puts out lots and lots of beautiful foliage. That is what I am after for propagating.

I have lots of these vines on the back fence. They are full sun, and they do bloom! Wonderful!

Janie

Hello, this thread may have been from 2006 and it's 2022 now. May I add mine... I live in the Philippines with a zone of 11. I tried growing cuttings last year 2021 in the summer but failed. This time, I made it in cooler June when it is a rainy season and very humid and less hot. I make cuttings of green stems only, and make sure the cut is right under the nodes where new leaves grow, and that the cut should be clean, not using a dull scissor that may crush the tip. After, I add a drop of rooting hormone on the cut ends and immediately stick to the soil. I constantly mist them and keep away from direct sun, but in bright area. The roots appear within a week.