How to Plant Dipladenia (Mandevilla)
Planting dipladenias is a surefire way of brightening up your home or garden. Now commonly known as mandevilla plants, the showy blooms and glossy green leaves of dipladenia plants (Mandevilla sanderi) and white dipladenias (Mandevilla boliviensis) make them a sought-after houseplant and garden plant in USDA hardiness zones 10 and 11.
These vigorous vines are sensitive to their surroundings and they must be grown under the right conditions to produce their stunning flowers, but the process of planting them is not difficult.
Dipladenia is no longer the genus name for this group of showy, flowering vines that now bear the genus name Mandevilla—but dipladenia is still used as a common name in some cases. Brazilian jasmine is also a common name for Mandevilla sanderi.
Choosing a Growing Site
For tropical vines such as dipladenia, growing indoors and in greenhouses is best. They are extremely sensitive to cold and should only be grown outdoors in the warmest frost-free climates unless you plan to grow them in pots and overwinter them indoors.
- Position dipladenia plants near a south-facing, sunny window where they will receive full sun. Unshaded west-facing windows may also work, but the vine may produce fewer of its trumpet-shaped flowers. Shade will diminish blooming and cause leggy growth, so do not place these plants near a north-facing window. Dim light also causes smaller flowers to form.
- Choose a location away from heater vents, because hot, dry air can cause the leaf edges to burn.
- Position dipladenia plants where they will receive plenty of direct sunlight, but avoid planting them against an unshaded south-facing wall. Provide light shade all day long in hot, humid climates.
- Amend the growing site with a 2- to 3-inch layer of compost worked into the top 8 inches of soil, if the soil is heavy clay or sand.
- Potted dipladenias should be grown in a location with morning sun and light shade during the hottest part of the day.
Planting Dipladenias in Pots
Potted dipladenias should be planted in spring when daytime temperatures stay above 70°F and nighttime temperatures stay above 60°F.
- Cover the bottom of the pot with standard soil-based potting mix or a potting mix made of equal parts potting soil, peat moss and coarse sand. Settle the root system onto the soil layer. Tease apart the roots if they are pot-bound.
- Hold the plant up so that the base of the stems is 2 inches below the top of the pot. Add potting soil by the handful until the roots are covered to the same level that it was in its original pot.
- Water the plant to settle the soil around the roots. Add more soil, if the roots become exposed after watering.
- Insert a small wire trellis into the back of the pot to support the vine as its grows, or position the pot near the base of an existing structure, whether it is a trellis or a fence.
According to the National Gardening Association, dipladenia plants need a container that is 3 gallons in volume or greater with drainage holes at the base. Plastic pots weigh less and are easier to move than clay pots, but unglazed clay pots can help keep a plant's roots healthy by regulating moisture levels in the soil.
Planting Dipladenias in the Garden
Plant dipladenia in the garden in spring after the soil warms and all frost danger has passed. In frost-free climates, dipladenia can also be planted in autumn.
- Dig a hole that is just deep enough to hold the dipladenia’s root ball. Make the hole a few inches away from the base of a trellis or other structure.
- Remove the dipladenia from its original pot and tease apart the roots. Settle it into the hole so that the base of the stems is at the same level as the surrounding soil.
- Fill in the hole with soil until the roots are completely covered. Gently firm the soil, but don’t press it too much or water may not soak in as well.
- Spread a 2-inch-thick layer of mulch over the root zone. Leave a gap of a few inches between the plant and the mulch layer to prevent stem rot.
Growing Dipladenia Plants
Dipladenia plants require a moderate amount of care whether you are growing them outdoors in the garden or growing them indoors in pots.
Water: Provide dipladenia plants with 1 to 2 inches of water each week. Overwatering can lead to problems such as root rot, so always let the soil dry out slightly between waterings.
Fertilizer: Dipladenia plants are moderately heavy feeders, especially when grown under high light conditions. Feed weekly during the growing season with 1/2 teaspoon of liquid plant food mixed into 1 gallon of water. Start feeding when new growth appears in spring and stop feeding after midsummer to allow the plant to rest.
Pruning: Dipladenia needs pruning at the end of winter to make way for new growth. Prune back the old, dead growth to ground level using sharp, clean pruning shears. Overgrown dipladenia vines can also be cut back to control their size.
Pest Problems: Major problems are rare if dipladenia plants are grown under good conditions, but they can sometimes develop infestations of spider mites and mealybugs when grown as an indoor plant. Periodically look for small bugs on the undersides of the dipladenia leaves. Treat the pests with horticultural oil as soon as they are noticed.
Sasha Degnan holds a Bachelor of Arts degree in English Literature and Anthropology. Her written work has appeared in both online and print publications. She is a certified Master Gardener and dedicated plant enthusiast with decades of experience growing and propagating native and exotic plant varieties.