The common garden flower Cosmos is a popular, easy-to-grow annual, celebrated for its cheerful, daisy-like blooms that blanket a garden from summer until the first frost. These plants produce an abundance of bright, accessible flowers, leading gardeners to wonder if they serve as a food source for hummingbirds. Hummingbirds are unique pollinators, relying on specific floral characteristics to fuel their high metabolism. This article explores whether the open, composite structure of a Cosmos flower meets the energetic requirements of these tiny, hovering birds.
Cosmos Flowers and Hummingbird Visits
Hummingbirds do visit Cosmos flowers, but these blooms are generally considered an opportunistic or secondary food source. The bright colors of many Cosmos varieties, particularly red, orange, and hot pink, act as a visual beacon for the birds. The sheer volume of flowers produced by a well-established patch makes Cosmos a readily available target.
However, the architecture of the Cosmos flower head presents a challenge for efficient nectar collection. The flowers are composite, meaning the nectar is contained in numerous tiny florets clustered at a shallow depth. This open structure is not ideally suited for the hummingbird’s long, slender bill, which is designed to probe deep into tubular blooms. Extracting nectar requires the bird to expend energy hovering.
The flower type within the Cosmos genus influences the likelihood of a visit. Single-petal varieties, where the central florets are exposed, offer easier access to the available nectar. Conversely, double or frilly-petaled varieties can nearly block the central nectar source. The resulting energy gain may not justify the effort, making Cosmos a low-priority stop.
Why Hummingbirds Prefer Specific Flower Shapes
The feeding habits of a hummingbird are driven by energy efficiency, dictated by the match between the bird’s bill and the flower’s structure. The most preferred flowers possess a long, tubular or trumpet shape adapted to the hummingbird’s bill. This tubular design ensures the bird inserts its bill, placing pollen directly onto its head for transport to the next bloom.
This deep structure also shields the nectar from consumption by insects like bees, which cannot reach the sugar source. The correspondence between the length of a hummingbird’s bill and the depth of the flower’s corolla tube maximizes the speed of nectar retrieval. Flowers that offer this precise fit allow the bird to drink quickly and move on, minimizing the energy spent hovering.
Hummingbirds are also highly sensitive to color and nectar quality. They prefer flowers in the red, orange, and pink spectrum, colors less visible to many insect pollinators. This color preference helps reduce competition for their food source. The nectar must contain a high concentration of sugar, typically 20 to 25% sucrose, to fuel their rapid metabolism. Flowers with lower sugar content are often bypassed for those providing a substantial caloric reward.
Creating a Hummingbird-Friendly Garden
Transforming a garden requires focusing on planting choices that align with the hummingbird’s energetic needs. The most effective strategy involves mass planting flowers with the preferred tubular shape, maximizing visual impact and feeding efficiency. Examples of ideal flowers that offer a deep, narrow corolla include:
- Scarlet Sage (Salvia)
- Bee Balm (Monarda)
- Cardinal Flower (Lobelia cardinalis)
- Firecracker Plant (Cuphea)
Planting flowers in large clusters, rather than scattered singly, creates bold patches of color that hummingbirds can easily spot from a distance. Select varieties that bloom at different times to ensure a continuous nectar supply from early spring through late fall. Combining tall flower spikes, such as Penstemon, with mid-height bloomers like Agastache provides multiple feeding levels and clear flight corridors.
Supplementary feeders provide sustenance, especially during migration periods. The artificial nectar should be a simple solution of one part white granulated sugar to four parts water, mimicking natural sugar concentration. Avoid using red dyes, honey, or artificial sweeteners, as these can be harmful. Placing feeders near natural perches and providing a fine misting device or shallow water source also supports their needs for preening and hydration.