This dataset consists of flower density values of common British plant species. The data were collected during field surveys taking place from February to October in 2011 and 2012. The majority of field sites were located in the south of England. The data were collected under a project named 'Agriland' ( Linking agriculture and land use change to pollinator populations) based at the University of Bristol, as part of the UK Insect Pollinators Initiative. The Insect Pollinators Initiative (IPI) was funded by Biotechnology and Biological Sciences Research Council (BBSRC), Natural Environment Research Council (NERC), Department for Environment, Food and Rural Affairs (Defra), the Scottish Government and the Wellcome Trust, under the auspices of the Living With Environmental Change (LWEC) partnership.