Pollinators play a crucial role in the ecosystem, human health, and the economy. However, despite the significance of pollinators, their populations are declining globally. Pycnanthemum is a marketable pollinator-attractive plant that could supplement pollinator resources in the landscape. Breeders would benefit from a comparison of the pollinator attractiveness between Pycnanthemum species and accessions. Cultivating Pycnanthemum should focus on aesthetic traits and maximizing pollinator abundance and species richness. Pollinator visitation was compared among three species and five accessions of Pycnanthemum (P. flexuosum (F), P. virginianum (V), and three accessions of P. tenuifolium (T1-T3)) using observations and capture. Lepidoptera, honey bees (Apis mellifera), Diptera, carpenter bees (Xylocopa spp.), small bees, and bumble bees (Bombus spp.) were observed most abundantly on Plant F. Plant V attracted the highest number of pollinators overall, with Apis mellifera (honey bees) accounting for more than half of the pollinator visitation. Xylocopa spp. (carpenter bees) and honey bees did not have a significant preference between the species. Plants F, T2, T3, and V attracted the greatest abundance of Diptera (flies). Wasps were most attracted to Plants T3 and V, while Bombus spp. (bumble bees) was observed most often on Plants F and V. Plant F attracted the highest number of Lepidoptera (butterflies and moths) and small bees. The species richness of pollinators did not significantly differ across Pycnanthemum species, with at least 24 to 29 different pollinator species visiting each plant. A range of factors, including olfactory cues, the morphology of plants, and accessibility of resources, may have affected pollinator preferences. Determining which Pycnanthemum species attracted an abundance and diversity of pollinators provides breeders a foundation for cultivation and conservation expectations.
