Although mandevilla (Mandevilla splendens) can be fussy, the spectacular blooms are worth the extra tender care required to keep the plant lush and healthy. Mandevilla is not cold-tolerant and is hardy only in the tropical southern climates or United States Department of Agriculture (USDA) zones 10 through 11. In most climates, mandevilla should be planted in a patio pot or a hanging container, so that the plant can be brought indoors for much of the year.
Place mandevilla in bright, indirect sunlight. Mandevilla will do well in filtered light, near a window covered with a filmy curtain, or four to five feet away from a sunny window. Outdoors, the pot should be placed in partial shade, where the plant will be protected during hot afternoons.
Keep room temperatures moderately warm with daytime room temperatures above 70 degrees Fahrenheit, and nighttime temperatures between 60 and 65 degrees Fahrenheit.
Water mandevilla until water runs through the drainage holes in the bottom of its pot. Allow the potting soil to drain thoroughly, before placing the pot back onto the drainage saucer. Water again in about a week, or when the soil feels slightly dry to the touch.
Feed mandevilla every other week, using a fertilizer high in phosphorus, with a ratio of 10-20-10. Apply the fertilizer according to the manufacturer's recommendations. Withhold fertilizer during the winter months.
Place your mandevilla plant outdoors during the warm weather months. Bring the plant back indoors before night time temperatures drop below 50 degrees Fahrenheit.
Prune mandevilla in late winter or early spring. Remove old, woody growth and branches that rub or grow across other branches. Shorten branches as needed to maintain size and shape. Place a stake or a small trellis in the container, to support the vines if the mandevilla is not planted in a hanging container.
Things You Will Need
- 10-20-10 fertilizer