Drunk on nectar? I've seen them rolling on their backs in eryngium flowers
Tree suckers, what's the tree in the bottom photo?
Cherry and plum, and the wild species of those, are very good at suckering.
Is that a new plant to your garden Margot? If you think it may have been treated with nasties you could remove the flowers, the next lot will probably be OK.
But bees have a short life, maybe nothing to do with the plant
sounds a great addition to a car park to me.
You'll need a big pot in a few years
they're fast when they get going. The annual growth on a coppiced specimen is amazing.
Trees aren't usually quick in the first few years
nothing to lose, they won't be alive by next year.
they both have coarse hairy leaves.
My money stays on the Pentaglottis
or possibly Green Alkanet, Pentaglottis sempervirens
Some sort of Verbena.
Maybe Verbena hastata