Phacelia buzzing

In one corner of the rosybee site we plant 'crops' specifically to provide the bees with a boost. These always include sections of borage and phacelia because, for a large area, they provide maximum benefit and are very reliably grown by scattering the seed on the surface (as we don't have any seed drill machinery).  For the last two weeks the phacelia has been in full flower and buzzing. I have never heard such a loud noise from bees while foraging. It is really quite an experience to stand in the middle of that sea of pale purple flowers and be surrounded by a mix of bumblebees and honeybees manically darting from bloom to bloom. The bees I spotted included honeybees, buff-tailed, red-tailed and garden bumbles, common and moss carders, and I think I even saw hairy-footed flower bee. It was difficult to count bee density because they were moving so fast but it averaged around 12 bees per square meter, which is very high.  Fabulous.