If you love plants that add loads of color to your landscape or outdoor living area, the Mandevilla or rock trumpet is the perfect addition. This vigorous, tropical vine makes an excellent container plant but also thrives in flower beds in coastal and southern regions. Large trumpet or funnel-shaped flowers bloom in late spring and continue until the first frost. The Mandevilla is easy to grow and doesn’t require a ton of maintenance or special care.
Gardeners who live in USDA plant hardiness zones 9 and above, where winter temperatures don’t drop below 45 to 50 degrees, can grow this plant as a perennial in landscape gardens. It dies back to the ground come winter, but its roots survive. In the spring, the Mandevilla emerges again, ready to bloom for another season. In areas that receive frost, however, the plant is an annual. Remedy the issue by planting them in containers and bringing them indoors before the cold weather arrives.
Light is energy for a plant. The more light it receives, the more energy the plant creates, and the faster it will grow. The Mandevilla needs six to eight hours each day to produce the magnificent, five-petaled blooms it’s famous for. Indirect or filtered sunlight is best. The benefit of planting Mandevilla in pots is that you can relocate them as needed if the sun gets too hot; if mid-day temps are extreme, move your plant to a shadier spot, as super-intense sun rays can scorch it. Tie them down if you live in a windy area to avoid damage.
Well-drained, sandy soil works best for the Mandevilla, but a healthier organic soil mix is even better. Try adding two parts peat moss or potting soil to one part builder’s sand. You can also add in some organic material, such as leaf mold — composted leaves that will increase the water retention in your soil.
Too much water leads to soggy soil and unhappy roots. On the other hand, if the soil becomes too dry, the leaves of the Mandevilla will droop and the plant won’t thrive. Therefore, keep the soil moist, but not super-wet. Once-a-week waterings work well, but it depends on the variety and size of the plant, the amount of sunlight it’s getting, and the temperature around it. Always check the soil before watering.
Newly purchased plants usually have fertilizer already added into their soil. A few months after you’ve planted the Mandevilla, add a slow-release fertilizer or a water-soluble, diluted plant food every other week. Always monitor for any changes after you’ve fertilized it because you may need to adjust its feeding schedule. Some growers suggest a one-time feeding of high-phosphorus fertilizer at the end of the summer to see the plant through the winter.
Most people say you can’t over-prune a Mandevilla. Better yet, they say you can prune it at any time of the year. Your inspiration: the more you prune it, the more it blooms. Pinching is also an effective strategy to encourage healthy growth. Use your finger and thumb to pinch 1/4- to 1/2-inch lengths off the end of the stems to encourage luxuriant foliage and a bushier, fuller, plant.
Whether you plant them in containers or the ground, the Mandevilla adds color and curb appeal to entryways and other focal points of your home. The vines will find their way up and around any narrow post or support, and you can use fishing line to guide them. Plant Mandevilla in containers near a structure and you’ll soon see a vibrant mass of lush flowers surrounding it. Indoors, add a trellis or other support structure to train vines for big splashes of color. Choose an area that allows your Mandevilla plant plenty of room to flourish.
There are tons of Mandevilla varieties and a long list of colors to choose from. Some blooms are intensely fragrant; others, like the pink Alice Dupont variety, emit a more delicate scent.
Botrytis blight, or gray mold, occurs mostly during cooler weather or if the grower uses overhead watering methods on their Mandevilla. The foliage wilts and brown spots appear on the leaves and stems. Neem oil or copper salts can get rid of the problem. Crown galls are large knob-like growths that appear around the base of the vine. This bacterial pathogen restricts both nutrients and fluids from traveling to the plant’s roots and, unfortunately, Mandevilla that develop this infection must be destroyed.
Some experts speak of Dipladenia and Mandevilla as if they were the same plant, but they aren’t. Botanists classify both in the genus Mandevilla and their flowers are similar. Mandevilla is a creeper — a climbing vine with long, rough-textured, narrow leaves. The Dipladenia is also a vine, but it’s smaller and more shrub-like, with thicker, pointed, heart-shaped leaves. While the Mandevilla is a beautiful choice to enhance a trellis, pergola, arbor, porch, or entryway, the Dipladenia doesn’t vine as easily but grows beautifully in hanging baskets and pots.