The decline in pollinator populations has been documented worldwide in recent years with many researchers focusing on the matter. Many people are interested in ornamental annuals they can plant in their garden to better support pollinators and have many varieties and cultivars to choose from. However, there is a lack of research behind what specific cultivars of ornamental annuals are attractive to pollinators. We sampled pollinators visiting six cultivars of Tagetes spp. (marigold), eight cultivars of Portulaca spp. and ten cultivars Bidens spp. separately for two years to evaluate each cultivars relative pollinator attractiveness among each annual. Pollinators collected were categorized into four groups, Apis mellifera, Bombus impatiens, Wild Bees and Syrphids, to show the proportion of different pollinator visitors to each cultivar. There was significant variation among individual cultivar pollinator visitation rates found for each annual, with some cultivars having over double the visitation rate of others. We also evaluated nectar production and nectar quality of two selected Portulaca spp. and Bidens spp. cultivars based on first-year pollinator visitation data collected as a means of showing a possible reason for varying pollinator visitation among cultivars. Our results show clear pollinator preferences for certain cultivars, and that nectar production and nectar quality may be a driving influence. This research will better inform entomologists, horticulturalists, growers, and educators which of the selected cultivars of Tagetes spp. (marigold), Portulaca spp. and Bidens spp. have higher pollinator visitation, and that cultivar differences should be considered when labeling a plant as ‘pollinator-friendly’.
Read
