Perennial ground cover plants as floral resources for urban pollinators: A case of Geranium species

Urban green areas, due to their high plant diversity, can be supportive as floral resources (nectar and/or pollen) to wild and managed pollinating insects. This research aims towards understanding the contribution of ornamental ground cover perennials as a food source for urban pollinators. We compare floral phenology and abundance, nectar and pollen production, and insect visitation to flowers of Geranium macrorrhizum, G. platypetalum and G. sanguineum, planted in the botanical garden of Lublin, SE Poland. The investigation revealed that the studied hardy geraniums exhibit many features valuable for pollinators, including large floral display (G. macrorrhizum and G. platypetalum), extended flowering period (G. sanguineum) and ample nectar and pollen reward (G. macrorrhizum). They can supply urban pollinators with a high quality food during spring and early summer time, i.e. the period of high food demand by many bee species. Moreover, hardy geraniums might be valuable plants for urban beekeeping as they are eagerly visited by honeybees. The investigated ground cover plants could therefore be considered in future city plantings.