Mandevilla is a hardy tropical perennial that is grown as a house plant in most climates, taken outdoors in the summer and indoors during colder seasons. Mandevilla plants have trumpet-shaped pink, yellow or white flowers and puckered, oval leaves on twining vines. Named after the British diplomat and gardener Henry Mandeville, the mandevilla is lovely plant that is easy to propagate by either planting seeds or cuttings. You can start another mandevilla plant by taking cuttings from your existing mandevilla.
Take a cutting from your mandevilla in late summer or in autumn using clean, sharp pruning shears. Cut a two- to three-inch-long tip or side shoot with firm growth that is not new, light-green growth.
Remove all the leaves except for the two top ones. Dip the cutting's raw end in rooting hormone.
Insert the cut end in a small planter pot filled with a sandy peat soil mix. Place the pot in a plastic bag and tie it closed at the top.
Place the pot in a shaded area that is away from direct sunlight. Open the bag periodically to release any excess moisture.
Remove the plastic bag and place the planter pot in bright, indirect sunlight when new growth appears and the roots begin to develop. This can take anywhere from 20 to 70 days.
Transfer the new mandevilla plant to a larger planter pot as it grows, before it becomes rootbound. After the mandevilla develops strong roots, you can plant it outside in a partially shady spot if you live in a tropical or subtropical climate.
Feed your new mandevilla plant a high-phosphorous fertilizer, such as a 10-20-10, every two weeks during the spring and summer. Follow the dosage instructions on the fertilizer packaging. As the plant begins to grow, erect a trellis to support its long, trailing vines.