Herbaceous perennial ornamental plants can support complex pollinator communities

Abstract

Abstract Human-designed landscapes can host diverse pollinator communities, and the availability of floral resources is central to supporting insect biodiversity in highly modified environments. However, some urban landscapes have relatively few pollinator-attractive plant species and management in urban environments rarely considers the function of these plants in generating and supporting a stable ecological community. Evaluations of 25 cultivars within five commercially popular herbaceous perennial ornamental plant genera (Agastache, Echinacea, Nepeta, Rudbeckia, and Salvia) revealed variation in the total and proportional abundance of visitors attracted. These varieties supported multiple pollinator functional groups, however bees were the primary visitors to in this system. Cultivars were assessed according to their function within a plant–pollinator network. Comparisons of artificial networks created with the six most attractive and six least attractive cultivars demonstrated that a planting scheme using the most attractive cultivars would attract nearly four times as many bee species, including several specialists and rare species. Plant diversity in the landscape was correlated with abundance and diversity of pollinator visitors, demonstrating that community context shapes a plant’s relative attractiveness to pollinators. We conclude that herbaceous perennial cultivars can support an abundance and diversity of pollinator visitors, however, planting schemes should take into consideration the effects of cultivar, landscape plant diversity, floral phenology, floral area, and contribution to a stable ecological community.