Quantifying variation among garden plants in attractiveness to bees and other flower‐visiting insects

Summary Pollinating insects are globally declining, with one of the main causes being the loss of flowers. With the value of countryside reducing, urban areas, particularly gardens, are increasingly recognized as of benefit to wildlife, including flower‐visiting insects. Many gardeners specifically select plant varieties attractive to wildlife. Given the wide public interest, many lists of recommended varieties have been produced by both amateurs and professional organizations, but appear not to be well grounded in empirical data. These lists, however, are not without merit and are an obvious starting point. There is clearly a need to put the process onto a firmer footing based more on data and less on opinion and general experience. We collected data over two summers by counting flower‐visiting insects as they foraged on 32 popular summer‐flowering garden plant varieties in a specially planted experimental garden, with two smaller additional gardens set up in year two to check the generality of the results. With many thousands of plant varieties available to gardeners in the U nited K ingdom, and other countries or regions, it would have been an impossible task to make a comprehensive survey resulting in a complete and authoritative list. Our results are valuable and encouraging. Garden flowers attractive to the human eye vary enormously, approximately 100‐fold, in their attractiveness to insects. Insects, especially bees and hover flies, can be attracted in large numbers with clear differences in the distribution of types attracted by different varieties. Our results clearly show that there is a great scope for making gardens and parks more bee‐ and insect‐friendly by plant selection. Horticulturally modified plant varieties created by plant breeding, including hybrids, are not necessarily less attractive to insects and in some cases are more attractive than their wild‐type counterparts. Importantly, all the plants we compared were considered highly attractive to humans, given that they are widely sold as ornamental garden plants. Helping insect pollinators in gardens does not involve extra cost or gardening effort, or loss of aesthetic attractiveness. Furthermore, the methods of quantifying insect‐friendliness of plant varieties trialled in this study are relatively simple and can form the basis of further research, including ‘citizen science’.