Q. Can African milk tree (Euphorbia trigona) be rooted in water?
Euphorbia trigona is a succulent euphorbia grown for its decorative stems. It should not be rooted in water or it will rot. To propagate this plant, you take a stem cutting in late spring or early summer.
Stopping the flow of milky sap is important to the health of the parent plant and the cutting. Dip the cutting end in water and spray the parent's would with water. Then let the cutting dry out ("heal") for a few days to avoid disease. Prepare a pot of moistened peat moss and perlite, mixed in equal amounts, with a layer of sand on top to prevent rot. Insert your cutting into the potting mix and place it in filtered light at normal room temperature.
Keep the potting mixture just barely moist for about two months. At that point roots will have formed and new growth will appear on the cutting. You can repot the plant in succulent potting mixture and treat the plant as a mature euphorbia.
Good luck with your propagation!
Courtesy of NYBG Plant Information Service