The Dipladenia vine, more commonly referred to as Mandevilla, is a woody vine that produce non-stop colour in your garden during the growing season. The best method of propagating this vine is by cutting softwood sections of new growth off the ends. Softwood growth has a green-tinge colour and is flexible when bent. Dipladenia produces roots quickly, about two to three weeks after starting the propagation process.
Clip 6-to 8-inch-long softwood cuttings off the Dipladenia vine from late spring through early summer. Wrap all cuttings in a damp paper towel and place in a plastic bag immediately after cutting.
Wash a propagation tray with soap and water and rinse well to remove all residue. Wipe the tray dry with a paper towel.
Fill a propagation tray with propagation medium. Mix the medium with water until it forms the consistency of a damp sponge. Use your hands to work the soil thoroughly.
Remove the cuttings from the plastic bag and clip off leaves from the lower half. Dip the bottom end of the cutting into rooting hormone powder and stick immediately into the propagation medium to a depth of about 3 inches. Space the Dipladenia vine cuttings so the leaves do not touch in the tray.
Poke long craft sticks evenly throughout the propagation tray to hold the plastic off the cutting. Slide the tray into a clear plastic bag and tie closed with a rubber band or twist tie. Set the tray in an area with indirect light and a temperature of 20 to 21.1 degrees Celsius.
Open the plastic bag one to two times a day to refresh the air around the cuttings and check the moisture level. Mist the medium with water to keep it the consistency of a damp sponge.
Pull on the vine cuttings about two weeks after sticking in the medium to see if there is resistance from the growth of roots. Move the soil around the base of the cutting to verify the root length.
Transplant the Dipladenia cuttings into 4-inch pots once the roots are over 1 inch long. Use a well-draining potting soil and moisten it with water before transplanting the cuttings. Grow the cuttings indoors to strengthen the plants before transplanting them outdoors the following spring.