Mandevillas are popular flowering plants known for their stunning, trumpet-shaped blooms and tropical charm. These vigorous vines bring vibrant color and exotic beauty to any garden or patio, adding vertical interest throughout warmer months.
Understanding Mandavillas
Mandevillas, also known as rocktrumpets or dipladenia, are tropical vines native to Central and South America. They are characterized by glossy green leaves and a continuous display of large, five-petaled, trumpet-shaped flowers. While many varieties are vining, newer cultivars offer compact, mounding growth suitable for containers. Their blooms come in various shades of pink, red, white, and yellow, often with a contrasting yellow throat. In warmer climates (USDA Zones 9-11), mandevillas grow as perennials, reaching 3 to 10 feet, but in cooler regions, they are typically cultivated as annuals or brought indoors.
Planting and Ongoing Care for Mandavillas
Location and Soil
Mandevilla plants thrive in locations with ample sunlight and well-draining soil. They prefer at least six hours of direct sunlight daily for abundant flowering. In regions with intense summer heat, some afternoon shade helps protect foliage from scorching. When planting, ensure the soil is rich in organic matter and drains freely, as mandevillas dislike soggy roots. A slightly acidic to neutral soil pH (6.0-7.5) supports healthy growth.
Watering
Consistent moisture benefits mandevillas, though they tolerate some dryness. Water when the top inch or two of soil feels slightly dry, ensuring the entire root system is saturated. Allow excess water to drain completely from pots to prevent waterlogging. During very hot weather, container-grown mandevillas may require daily watering, while in-ground plants need less frequent attention.
Fertilizing
Regular fertilization during the active growing season encourages continuous blooming and healthy plant vigor. Begin feeding in spring as new growth emerges and continue through summer. A balanced liquid fertilizer (e.g., 10-10-10 or 20-20-20) applied every one to two weeks, or a high-phosphorus formula, works well. Slow-release granular fertilizers can also be applied once in spring. Always water thoroughly before applying fertilizer to aid nutrient absorption and prevent burn.
Pruning
Pruning mandevillas helps maintain shape, encourages bushier growth, and promotes abundant flowers. The best time for significant pruning is late winter or early spring, before new growth starts. Since flowers primarily form on new growth, this stimulates new shoots. Trim leggy or overgrown vines to just above a set of leaves, removing up to one-third of the plant’s mass. Pinching new shoot tips early in spring also encourages branching and a fuller plant.
Overwintering Mandavillas
For gardeners in regions with cold winters, mandevillas must be brought indoors to survive, as they are sensitive to temperatures below 50°F (10°C). Before the first frost, inspect the plant thoroughly for pests to avoid introducing them indoors. You can choose to overwinter them as houseplants or allow them to go dormant.
As a Houseplant
Prune the plant to a manageable size, cutting back vines by up to one-third or more. Place it in a location with bright, indirect light, such as a sunny window. Reduce watering, allowing the top inch or two of soil to dry between waterings, and suspend fertilization entirely. Maintaining some humidity, through misting or a pebble tray, can also be beneficial.
To Induce Dormancy
Cut the plant back more drastically, leaving only a few inches of stem. Store it in a cool, dark place where temperatures remain above freezing, ideally around 50°F (10°C). Water very sparingly, just enough to prevent the soil from becoming bone dry, and do not fertilize. The plant may drop leaves, which is a normal part of dormancy.
Common Problems and Solutions
Mandevillas are generally resilient, but they can encounter a few common issues. Yellowing leaves often indicate improper watering (too much or too little) or a nutrient deficiency. Ensure the soil is consistently moist but never waterlogged, and consider a balanced fertilizer if nutrient lack is suspected.
Pests such as aphids, mealybugs, spider mites, and scale insects can sometimes affect mandevillas. Aphids cause new leaves to distort, mealybugs leave cotton-like masses, and spider mites cause yellow mottling. For minor infestations, a strong spray of water can dislodge pests, or insecticidal soap and neem oil can be effective treatments.