Mandevilla, also known as rocktrumpet, is a popular flowering vine often used by gardeners to attract hummingbirds. Mandevilla flowers can be an effective nectar source, but the level of attraction depends highly on the specific variety of the plant. This vibrant climber, native to Central and South America, features trumpet-shaped blooms that align with the feeding preferences of hummingbirds. Understanding the biological reasons behind a hummingbird’s flower choice explains why some Mandevilla varieties are better magnets than others.
The Tubular Attraction: Why Hummingbirds Choose Certain Flowers
Hummingbirds and the flowers they feed on have a long history of co-evolution, resulting in distinct floral preferences. A flower’s shape is a primary factor; hummingbirds are drawn to tubular or trumpet-shaped blossoms that perfectly accommodate their long, slender bills. This structure often limits access for insects, reducing competition for the nectar.
The color of the flower is another significant visual cue, with hummingbirds exhibiting a strong attraction to the red and orange ends of the light spectrum. While they do not exclusively visit red flowers, this color signals the presence of nectar. Hummingbirds favor nectar with a high percentage of sucrose, a sugar they can metabolize efficiently to fuel their high-energy flight.
Assessing Mandevilla’s Appeal
The Mandevilla genus naturally produces trumpet-shaped flowers, which makes the nectar accessible to a hummingbird’s specialized feeding apparatus. Most single-flowered Mandevilla varieties present a clear path to the sugary reward.
The color of the bloom is also a determining factor in its effectiveness. Varieties featuring deep red or bright pink flowers are superior at attracting hummingbirds compared to those with white or yellow blooms. Highly hybridized types that produce “double flowers” (where the number of petals is increased) can inadvertently block the entrance to the nectar source, rendering the flower ineffective. Gardeners should select cultivars that maintain the original, open, trumpet structure to ensure the best chance of a visit.
Maximizing Hummingbird Visits and Alternative Plants
Optimizing the growing environment can increase hummingbird visits to your Mandevilla vine. The plant thrives in full sun, requiring at least six hours of direct sunlight daily. This encourages a prolific bloom cycle, providing a continuous nectar supply. Placing the vine on a trellis, arbor, or in a hanging basket provides vertical structure for the plant and perching spots for the birds.
If Mandevilla fails to draw attention, several other plants offer a more guaranteed attraction due to their consistently high-quality nectar and ideal flower structure. Excellent alternatives include species of Salvia, such as the vivid red ‘Hot Lips’ cultivar, which feature numerous tubular flowers. Another highly effective option is the Cardinal Flower (Lobelia cardinalis), which boasts spikes of scarlet tubular blooms. The Coral Honeysuckle (Lonicera sempervirens) is a non-invasive vine with bright red or coral-colored trumpet flowers that serve as a reliable native food source.