Bees are among the most industrious workers in nature, responsible for pollinating many of the world’s food crops and wild plants. Their choice of flower is not random, depending instead on a complex interplay of sensory cues and nutritional rewards. The answer to which flower is “best” is highly variable and depends on the specific bee species, its physiology, the local environment, and the time of year. Understanding a bee’s preference requires factoring in what it sees, smells, and can physically access.
How Bees Choose Flowers: Attraction Mechanisms
Bees possess a highly developed sensory system that allows them to efficiently evaluate a flower’s potential reward before landing. Their vision is attuned to the blue and violet end of the spectrum, as well as ultraviolet (UV) light, which humans cannot see. Many flowers feature patterns, known as nectar guides, that are only visible under UV light and function like a bullseye to direct the bee toward the nectar source. This visual guidance system helps to reduce the bee’s “handling time,” allowing it to forage efficiently.
Chemical signaling through scent is equally important, especially for initial attraction from a distance. Bees are typically drawn to fresh, mild, or sweet aromas, which are often honest signals indicating the availability of nectar and pollen. Specific chemical compounds, such as phenylacetaldehyde, have been shown to attract certain bee species, demonstrating a learned preference for reliable scent signals. Once on the flower, the bee evaluates the morphological structure, preferring blooms that offer a stable landing platform and easy access to the nectar.
Beyond visual and olfactory cues, a flower’s value is determined by the nutritional quality of its pollen and nectar. Nectar provides carbohydrates for energy, while pollen is the primary source of proteins and fats for the colony’s young. Bees quickly learn and remember which types of flowers consistently offer the best rewards, a behavior called flower constancy, which increases foraging efficiency and pollination success. This learned preference means that a flower offering a high protein-to-lipid ratio in its pollen may be chosen over a visually brighter one with less nutritious pollen.
The Highest-Ranked Flowers for Generalist Bees
Generalist pollinators, such as the European honeybee and many common bumblebee species, are attracted to flowers that provide high quantities of both nectar and pollen over a long blooming period. Several plant groups stand out as high-yield resources for these foragers. Specific herbs, including borage and catmint, are favored due to their intense scents and prolific production of nectar. Lavender and thyme, both members of the mint family, also offer small, numerous flowers that are easily accessible to a wide range of bees.
Among annuals and perennials, the daisy family, which includes sunflowers and coneflowers, ranks highly for generalist bees. Sunflowers are an excellent dual resource, providing abundant pollen and nectar, and their large, flat heads serve as convenient landing pads. Coneflowers and bee balm are also favored perennials that offer a long bloom period. These plants ensure a steady food supply throughout the summer and into the fall.
Trees and shrubs are often overlooked but represent significant early-season food sources. Willows are among the first plants to bloom in spring, offering pollen and nectar to bees emerging from hibernation. Maple trees also produce a large quantity of nectar from their modest flowers. Late-season bloomers like asters and Joe-Pye weed are equally important, offering a food bridge that sustains bees as they prepare for colder months.
Why Different Bees Prefer Different Blooms
The immense diversity among the thousands of bee species means that no single flower can be considered the universal favorite. Physiological differences, particularly tongue length, significantly determine which flowers a bee can effectively access. Long-tongued bees, such as some bumblebees, are equipped to reach nectar sequestered deep within tubular or hooded flowers, like foxglove or honeysuckle.
In contrast, short-tongued bees, including sweat bees, favor flowers with shallow or open structures, as they cannot reach the rewards in deeper blooms. These generalist flowers, like daisies or mints, offer easily available nectar and pollen. Some plants require a specialized foraging technique known as buzz pollination, where the bee vibrates its flight muscles at a specific frequency to release pollen trapped within the flower’s anthers.
Bumblebees readily engage in buzz pollination for crops like tomatoes and blueberries, unlike honeybees, which are less effective at this behavior. Some native bees are highly specialized and forage almost exclusively on a single plant family, such as the squash bee, which only visits squash, pumpkin, and gourd blossoms. This specialization highlights that the most attractive bloom is the one that has co-evolved perfectly with a specific bee’s body and dietary requirements.