Black-Eyed Susans (Rudbeckia hirta) are a familiar sight in North American gardens, often blooming from mid-summer into the fall. As a native wildflower, this species is appreciated for its bright yellow petals and its function as a resource for many insects. Bees are strongly attracted to them, as they provide a late-season source of both protein-rich pollen and energy-giving nectar. This common garden staple supports numerous beneficial insects, making it a productive addition to any landscape seeking biodiversity.
Floral Structure and Pollinator Appeal
The Black-Eyed Susan’s success as a bee forage plant lies in its composite flower structure, belonging to the Asteraceae family. What appears to be a single flower is actually a compact cluster of hundreds of tiny individual flowers, or disc florets, forming the dark brown central cone. The bright yellow ray petals surrounding the center are sterile and function as a visual target for visiting insects.
The small disc florets bloom progressively from the outer rim inward, offering a continuous supply of fresh pollen and nectar. This open, accessible arrangement allows many different types of bees to easily reach the pollen. Furthermore, the flowers possess ultraviolet patterns, invisible to the human eye, which guide bees directly to the reward at the center.
Specific Bee Species Interaction
The accessible nature of the Black-Eyed Susan’s composite head attracts a wide variety of bee species. Generalist feeders, such as European honeybees (Apis mellifera) and larger bumblebees (Bombus spp.), are frequent visitors, collecting pollen and nectar from the exposed disc florets. The structure is also beneficial for smaller, short-tongued native bees.
Solitary native species, including Little Carpenter bees (Ceratina sp.), Leaf Cutting bees (Megachile sp.), and Green Metallic bees (Agapostemon sp.), find the shallow florets easy to navigate. Coneflower Miner bees (Andrena rudbeckiae) are known to prefer flowers in the Rudbeckia genus. By supporting these various bee sizes and foraging styles, the plant contributes to the overall health of the local pollinator community.
Cultivation Practices for Maximum Pollination
To maximize the benefit Black-Eyed Susans provide to bees, gardeners should focus on specific cultivation methods. Planting the flowers in large clusters, or drifts, makes the resource more visible and attractive, increasing the foraging efficiency of visiting insects and encouraging them to stay.
It is best to select native, non-hybrid varieties of Rudbeckia hirta, as highly hybridized cultivars may have reduced pollen or nectar content. Gardeners must avoid using pesticides entirely, as even products marketed as bee-safe can harm insect populations. Allowing some spent flowers to remain and go to seed benefits birds and provides habitat for overwintering insects, further supporting the garden ecosystem.