The cuttings will root if they are mature branches. You will have to let the cuttings dry/callous for 2 to 3 days, then root in water but make sure they get filtered or morning sun. It takes 2 to 3 weeks for cuttings to root. Young cuttings will not root.
You can also hand pollinate your blooms to produce seedpods. Would love to see your desert roses in our Adenium forum.
