Hummingbirds are specialized avian foragers that rely almost entirely on flower nectar to fuel their extremely high metabolisms. Many gardeners seek to attract these iridescent visitors by selecting brightly colored flowers. This prompts questions about the suitability of common garden plants. This article explores whether the popular marigold is an effective choice, analyzing the specific biological and structural requirements of these unique birds.
Marigolds and Nectar Access
Marigolds (species of Tagetes) are generally not a preferred or efficient food source for hummingbirds. The primary reason for this avoidance is the physical structure, or morphology, of the typical marigold bloom. Hummingbirds are “hover-feeders” and require deep, tubular flowers that accommodate their long, thin bills for rapid, energy-efficient feeding.
The common marigold often displays a composite, open-faced structure or a dense, pom-pom shape that is difficult to navigate. This configuration fails to offer the deep, narrow chamber necessary for efficient nectar retrieval while hovering. The clustered petals of many varieties physically impede the bird’s bill from reaching the nectaries. Shallow or obstructed nectar access means the energetic reward is usually not worth the effort for the high-metabolism bird.
Visual Cues for Hummingbirds
Beyond physical structure, specific color wavelengths guide a hummingbird’s foraging behavior. Hummingbirds possess tetrachromatic vision, allowing them to perceive colors, including ultraviolet light, with greater complexity than humans. Research indicates a strong preference for flowers exhibiting red and orange hues, a pattern reinforced through co-evolution. These colors serve as a reliable visual signal, often indicating high sucrose concentration and avoidance by generalist insect pollinators.
While marigolds display bright yellows and golds, they typically lack the specific red wavelength that acts as the strongest feeding trigger. Yellow flowers often reflect UV light patterns that attract bees and butterflies, signals hummingbirds do not prioritize. Therefore, a structurally appropriate flower of a different color may be overlooked in favor of a true red bloom that advertises a rich, sugary reward.
Characteristics of Preferred Flowers
For gardeners aiming to attract hummingbirds, focusing on desirable plant traits is the most effective strategy. A high-quality food source must offer nectar with a significant sugar concentration, ideally ranging between 20 and 25 percent sucrose. This rich energy content ensures the bird gains more calories than it expends during feeding, which is essential for survival.
The flower morphology must create a precise mechanical fit with the bird’s bill length, promoting exclusive pollination. The flower must also reliably refill its nectar supply throughout the day to meet the bird’s continuous energy demands. The orientation of the flower is also important, as upward-facing or pendulous blooms are easier for a hovering bird to access without obstruction. Plants that embody these traits, such as upright salvia (Salvia splendens), penstemon, and trumpet-shaped petunias, are far more effective alternatives to marigolds.