I went outside into my garden and looked at all my lavender (it has self-set everywhere, as a "weed" is wanton to do, and I've dug it up and planted it in some form of order) - there's plenty of flowers and yet not a bee to be seen. It was really fucking depressing.
My balcony plants are absolutely frothing with bees, maybe that's where they all are. I'll tell them to go hang out at yours for a bit. They love the rosemary (which just keeps flowering all the time, it's insane) and the endlessly self-seeding calendulas and the odd native plants from an old planter from a former friend (there's bulbine lily and some kind of purple Asteraceae (Senecio maybe)).
That's awesome that you get so many on your balcony. And thank you, I'd love the little visit! I didn't check my rosemary as it's around the other side of the house, but I should have. Maybe they were all having a roast party or something and that's where mine were?