It sounds like you're keeping them too wet. They need to be evenly moist but not soggy. And I keep mine in the sun. I have to watch the water more carefully but I've had better luck that way.

Thanks seil, I'll try to move in a more enlightened position ...Do you cover your cuttings with something?Someone advised me to put 2 inches of agriperlite at the bottom of the plastic cup to improve air circulation, what do you think about?

Thanks for your advice

Last summer I took some cuttings and just used simple potting soil and vermiculite. I had bought this orbit mister I found online. I ran this mister daily with my cuttings even in the sun but by summers end I had two rose flowers open.