Mandevilla, also known as hoop plant or Dipladenia, produces showy flowers on climbing vines that reach up to 30 feet in length. The plant blooms twice per year, once during early summer and again in early fall, producing large quantities of fragrant, white flowers. Native to South and Central America, mandevilla requires consistently warm temperatures to thrive. In the United States, gardeners grow mandevilla in containers for easier transport indoors when temperatures drop below the plant's recommended range.
Site and Soil
Mandevilla grows best in potting mix consisting of one part peat moss, one part builder's sand and one part potting soil to provide adequate drainage. Daily temperatures of 70 to 85 degrees F and nightly temperatures of 60 to 65 degrees F are ideal. Mandevilla benefits from warm weather outdoors, but cannot tolerate temperatures below 45 degrees F. When outdoors, mandevilla requires partial shade for optimal growth. Provide bright, indirect sunlight for indoor plants. Make the most of mandevilla's long tendrils by planting in a hanging container and allowing the vines to hang over the side.
Watering and Fertilizing
Weekly applications of water prevent the soil from drying out completely, which is detrimental to mandevilla's health. Reduce the risk of foliar disease by applying water directly to the soil during the early morning so excess moisture can evaporate before temperatures drop in the evening. A high-phosphorous 10-20-10 NPK fertilizer applied once every two weeks during the spring and summer months provides mandevilla with necessary nutrition for growth and flowering.
Transferring mandevilla indoors to a lighted location during late fall protects against harsh winter temperatures, which kills the plant in most regions. Watering mandevilla once every 10 days helps induce a necessary dormant period, during which the plant drops most of its foliage. After winter ends and average outdoor temperatures rise above 50 degrees F, move the plant back outdoors to its original location.
Mandevilla requires regular pruning to stay healthy. The removal of all dead, damaged and diseased growth and the shortening of excessively long vines keeps mandevilla blooming and increases visual appeal. The use of pruning shears ensures clean cuts, which minimize damage and decrease the risk of fungal diseases.
Repotting mandevilla once every two to three years during late winter prevents the plant from becoming completely root-bound. A container 2 to 3 inches larger in diameter provides adequate additional room for growth. A fresh growing medium rejuvenates the plant and boosts new growth the following spring.