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Providing evidence to improve practice

Individual study: Plots of Phacelia tanacetifolia provide nectar (but not pollen) for bumblebees, at Rothamsted Research, Hertfordshire, England

Published source details

Williams I.H. & Christian D.G. (1991) Observations on Phacelia tanacetifolia Bentham (Hydrophyllaceae) as a food plant for honey bees and bumble bees. Journal of Apicultural Research, 30, 3-12


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Plant dedicated floral resources on farmland Bee Conservation

Williams & Christian (1991) planted three 9 m2 plots of phacelia at Rothamsted Research experimental farm, Hertfordshire, England. Seven species of bumblebee, including the long-tongued common carder bee Bombus pascuorum, and one cuckoo bumblebee B. [Psithyrus] vestalis foraged on the phacelia. Of observed worker bumblebee visits, 97% were for nectar, not pollen.

Plant nectar flower mixture/wildflower strips Farmland Conservation

A replicated study in 1989 in Hertfordshire, UK (Williams & Christian 1991) found that seven species of bumblebee Bombus spp., including the long-tongued common carder bee B. pascuorum, and one cuckoo bumblebee B. [Psithyrus] vestalis foraged on plots sown with phacelia Phacelia tanacetifolia. Of observed worker bumblebee visits, 97% were for nectar, not pollen. The plots each flowered for six to eight weeks, with a maximum flower density of more than 4,000 flowers/m2 on the plot sown in late May. The plot sown in July flowered until early December. Three 9 m2 plots of phacelia were sown at Rothamsted Research experimental farm in May and July 1989. Bee and flower densities were recorded weekly. Flowers were counted in a 0.25 m2 area of each plot. Bees were counted at 09:00, 11.00, 13.00 and 15.00 in each plot, their behaviour, species and gender were recorded.