Dipladenia is a tropical flowering plant often seen in nurseries, characterized by its glossy green leaves and vibrant, trumpet-shaped blooms. Native to the forests of Central and South America, this plant is frequently cultivated as a colorful annual in temperate climates. Botanically, Dipladenia is a vine, but it is typically grown to appear more like a compact, mounding shrub. This dual identity often confuses gardeners about how to best use the plant in their space. It offers a versatile appearance, serving as a spiller in a hanging basket or potentially climbing a small support with the right care.
The Vining Nature of Dipladenia
The natural growth mechanism of Dipladenia is that of a twining vine, meaning its stems wrap around a support structure rather than using specialized organs like tendrils or adhesive disks. These plants possess flexible, young stems that grow in a circular motion until they encounter a vertical object. The stems then spiral tightly, providing the mechanical support needed for the plant to ascend.
However, the Dipladenia varieties commonly sold are often cultivars specifically bred for a more compact, bush-like appearance. Commercial growers employ aggressive pruning, such as pinching back the growing tips, to encourage lateral branching. This technique forces the plant to divert energy into side shoots, resulting in a dense, mounding form desirable for container gardening and hanging baskets. Even in its compact form, the plant will still produce long, slightly sprawling stems that require management to maintain a tidy shape.
Clarifying Dipladenia vs. Mandevilla
Dipladenia’s growth habit is often compared to its close relative, the Mandevilla vine. Both plants belong to the same Mandevilla genus and share the same showy, trumpet-shaped flowers. The primary distinction lies in their growth vigor and leaf structure, which is a result of selective breeding.
Dipladenia varieties are typically bred to be much more compact, exhibiting a slower, more controlled growth rate and a naturally bushier silhouette. They feature smaller, thicker, and often more glossy leaves, which are better suited to container life. Mandevilla, in contrast, is the more vigorous, true climber, producing long, aggressive stems that can quickly ascend a trellis to heights of 10 to 20 feet under optimal conditions. Gardeners expecting the rapid climbing of a Mandevilla may find the slower, more compact nature of a Dipladenia disappointing.
Supporting and Shaping Growth
Gardeners can either train Dipladenia to climb or maintain its popular bushy form. To encourage climbing, provide a vertical support structure such as a small trellis, obelisk, or stake. The support should have a rough or textured surface, as the twining stems need something to grip onto as they wrap around the object.
Since Dipladenia is not a vigorous climber, manual guidance is often required in the early stages of growth. Gently wrap the young, flexible stems around the support and secure them loosely with soft ties to initiate the twining process. The plant will not climb a flat wall without a trellis, and the support should be placed near the plant’s base so the stems can easily find it as they begin to grow.
Maintaining a Bushy Form
If a bushy, mounding shape is preferred, simple pruning techniques can effectively maintain the compact form. Pinching back the new growth at the tips of the stems is the primary method. Removing the terminal bud forces the plant to break dormancy on the side nodes, resulting in increased lateral branching.
Pinching prevents the stems from becoming long and leggy. This should be done regularly throughout the growing season. By cutting the stem just above a leaf node, you redirect the plant’s energy into multiple side shoots, creating a denser plant. This dense form is ideal for hanging baskets or as a filler plant in mixed containers. Even when trained to climb, the side shoots can be pinched back to encourage a fuller appearance along the support.