The popular climbing vine, Clematis, offers significant resources to pollinators, particularly bees, but the benefit depends entirely on the specific variety planted. While bees are attracted to the vibrant colors and scents of the blooms, the actual reward—pollen and nectar—is not consistently available across all cultivars. For gardeners focused on supporting local bee populations, selecting the right Clematis bloom type is the most important decision.
The Core Attraction: What Bees Seek in Clematis
Bees are primarily drawn to Clematis by the promise of resources, with pollen often being the most significant offering. Many species of the vine produce large quantities of protein-rich pollen from numerous visible stamens in the flower’s center. This makes them an attractive forage option for generalist pollinators like bumblebees and certain solitary bee species.
The large, open nature of many Clematis flowers provides an easy landing pad, facilitating access to the central reproductive structures. While some varieties offer nectar, the main attraction for bees is the readily available pollen source, which they collect to feed their young. Native species, such as Clematis virginiana, attract a variety of insects, including leaf cutters and halictid bees.
The Crucial Difference: Why Flower Structure Matters
The physical structure of the Clematis bloom is the single most important factor determining its value to a pollinator. Open-faced, single flowers present their reproductive organs directly to visiting insects, allowing the bee to land easily and quickly gather pollen from the exposed cluster of stamens.
In contrast, many modern hybrid cultivars are bred for aesthetic appeal, resulting in complex, double-flowered, or “pompom” structures. These double forms occur because the pollen-producing stamens have been genetically modified to develop into extra petals (tepals), which reduces or completely eliminates the pollen source.
Even if some pollen remains, the multitude of extra petals creates a physical barrier, hiding the limited resources deep within the bloom. This makes it nearly impossible for a bee to reach the stamens or nectar, rendering the flower functionally useless for foraging. Gardeners must prioritize flowers with a simple, star-like structure over visual size and color.
Best Species for Pollinators and Garden Context
To ensure a Clematis is beneficial to bees, gardeners should select species known for their simple, open flowers. Small-flowered species, such as those in the Viticella group, are recommended for their high pollen yield and open structure. Examples include Clematis tangutica, which produces nodding yellow bell-shaped flowers, and Clematis integrifolia, a non-vining, herbaceous variety.
Native species like Clematis virginiana, often called Virgin’s Bower, are particularly effective and attract a wide range of native bees, including bumblebees. Early-blooming groups, such as C. alpina and C. macropetala, are also valuable because they provide resources early in the season when other flowers may be scarce. Planting a mix of these varieties helps create a continuous source of pollen from spring through late summer.