Hydrangeas are prized for their large, colorful flower heads that provide summer-long visual appeal. Many gardeners wonder if these popular shrubs offer value to the local bee population, especially as interest in supporting pollinators continues to grow. The common assumption that all large, showy flowers are a source of nectar and pollen is not true for all hydrangeas. The relationship between bees and these familiar shrubs is nuanced and depends entirely on the specific variety planted.
Not All Hydrangeas Are Equal
The genus Hydrangea includes a wide range of species and cultivated varieties, each with a different flower structure. Some types provide an accessible food source for bees, while others offer little to no nutritional reward. The level of bee interest is directly related to the shape of the flower cluster, which varies dramatically between cultivars.
The visual difference comes down to two main forms: the dense, rounded flower heads known as mopheads, and the flatter, more open clusters known as lacecaps. Mophead varieties, which are popular in cultivation, tend to have a structure that is largely inaccessible to foraging insects. The lacecap structure, conversely, presents the pollen and nectar in a way that is easily reachable for bees, butterflies, and other flying visitors.
Understanding Flower Structure and Pollination
The difference in pollinator appeal is rooted in the arrangement of two distinct types of florets found within a single hydrangea flower head: sterile and fertile. The showy, often four-petaled structures that create the massive, ball-shaped appearance of many hydrangeas are the sterile florets.
These sterile flowers are essentially modified leaves, or sepals, designed purely for visual attraction, acting as a large, colorful advertisement to insects. They lack the reproductive parts needed to produce pollen and nectar, meaning they offer no food reward to a foraging bee. For many ornamental varieties, particularly the classic mophead types of Hydrangea macrophylla, breeders have selected for plants with an overwhelming number of these non-productive florets.
The smaller, often inconspicuous flowers nestled beneath or in the center of the showy outer rings are the fertile florets. These small flowers contain the reproductive structures—the stamens with pollen and the nectaries—that bees seek for food. The evolutionary purpose of the large sterile flowers is to draw attention to these tiny, food-rich fertile flowers, ensuring pollination occurs. When a hydrangea variety is bred to maximize the size and density of the sterile florets, it often eliminates or deeply hides the fertile ones, rendering the plant useless to pollinators.
Choosing Varieties for Maximum Bee Appeal
Gardeners who want to support local bee populations should select hydrangea species and cultivars that feature a high proportion of accessible fertile flowers. The lacecap form of Hydrangea macrophylla is a good option, as it displays a central cluster of small, fertile florets surrounded by a ring of larger, sterile ones. This arrangement acts as a landing pad, guiding bees directly to the pollen and nectar source.
Beyond the common bigleaf hydrangeas, certain species are reliably better for pollinators due to their naturally high fertile floret count. These species offer a consistent food supply throughout the blooming season.
Recommended Pollinator Varieties
- The native Oakleaf Hydrangea (Hydrangea quercifolia) is highly attractive to bees and butterflies. Its elongated, conical flower clusters, which often turn from white to pink, are filled with easily reachable fertile flowers.
- The Panicle Hydrangea (Hydrangea paniculata) is one of the most popular types for pollinators, including bumblebees. Cultivars like ‘Limelight’ and ‘Pinky Winky’ have open flower structures that provide a rich source of nectar and often bloom for an extended period, offering a consistent food supply from mid-summer into autumn.
- Native Smooth Hydrangea (Hydrangea arborescens), such as the cultivar ‘Haas Halo,’ also features a flattened, accessible flower head with abundant fertile florets.
When shopping, look specifically for terms like “lacecap,” “fertile flowers,” or the species names quercifolia and paniculata. Avoid highly modified varieties that boast extra large, dense, ball-shaped blooms. By selecting varieties that prioritize the fertile floret structure, gardeners can ensure their hydrangeas are beautiful to humans and beneficial to bees.