Mandevilla vines, whether they are grown indoors or outdoors, need proper care and partial shade. Indoors, place the plants in a window that is filtered through a sheer curtain or in indirect, yet bright, sunlight. Outdoors, the mandevilla plants should be planted in an area that is partially shaded.
When given the right growing conditions, the mandevilla vine can grow 7 to 10 feet per season, climbing up fences and trellises with ease. Ideal temperatures for the mandevilla vine are 60 to 65 degrees at night and 70 degrees during the day.
Plant the mandevilla in sandy soil with humus added next to a fence or trellis. Pinch back the young vines to induce new growth and blooming.
The plants do not survive in temperatures that fall to less than 50 degrees Fahrenheit. In colder climates, it is necessary to bring in your mandevilla plants indoors for overwintering. If you live in a climate where it gets colder than 50 degrees in the winter, you may not want to let your mandevilla climb up a fence. You will want it to climb a trellis that you can bring along indoors during the winter. If your plant does climb a fence, a mailbox or a lamppost, you will probably need to cut the vines down to bring it inside. Not to worry. It will grow again next year as long as you keep it healthy through the winter.
Before you bring the mandevilla plant indoors, check every leaf and stem for insects and eggs. Remove whatever you find, and spray the plant down thoroughly with the hose before bringing it in. Pot them in equal parts peat moss, potting soil and sand. Place the plants in a well-lighted area where the temperatures are higher than 50 degrees but not too warm. Cut back the frequency of watering the plant during its resting time.
Lightly prune the mandevilla plant in late winter or early spring before new growth begins. The plant will bloom on the new shoots it produces!