Dipladenias originate in Brazil and are an evergreen flowering vine. Flowers come in many shades of red, pink, purple and pure white. Because the plant is hardy only in USDA planting zones 9 and 10, it is commonly found growing as a houseplant. The vines will grow to 6 to 8 feet and make great plants for hanging baskets. Dipladenias are slow climbers and can be pruned any time of year to keep them within bounds. In warmer climates, some cultivars will flower all year long.
Mix the soil for the container by adding 2 parts peat moss to 1 part potting soil and 1 part sharp sand; mix in a handful of crushed charcoal. It is absolutely essential that the soil drain well or the plant will not survive. Fill the container to within 2 inches of the top, leaving room for the plant and watering.
Create a hole in the center of the soil large enough to transplant the Dipladenia without crushing the root ball. Remove the plant from the container you purchased it in and knock off most of the growing medium from the roots. Place the roots in the planting hole and cover them with soil. Press down slightly to secure the plant.
Place the container in filtered or indirect light. Containers may also be placed outdoors whenever the weather is consistently over 50 degrees. Outdoors the plants can go in direct sunlight, however introduce the sunlight a little at a time to prevent burning. Winters should be spent in a window with six hours of southern sun a day.
Water until the water is running out of the drain holes. Keep the soil evenly moist throughout the spring and summer and allow to dry to touch during the fall. During the winter, Dipladenia should be kept fairly dry, watering only once a week.
Apply a 10-20-10 fertilizer every two weeks while the plant is growing. When flowering stops on the Dipladenia, so should the feeding. Resume feeding in the spring when you see new growth.
Start pruning to shape the plant only after you start to see growth in the spring. Pinch back growing tips to create a bushier plant. Deadhead flowers to keep the plant neat and avoid fungus disease.