This post also appears on my Facebook page:
Last year our Japanese pagoda tree flowered for the first time and was alive with bees, bumble bees, different types of wasps and other insects. I did put out a bowl of water which mainly attracted the local wasps. This morning, on Facebook, I saw a photo of a bowl of water and marbles put out for bees (sorry, I don’t remember where). The idea is that the bees can drink standing on the marbles and are less likely to fall in and drown. I seem to remember being told long ago that bees like shiny things, so in theory they will be drawn to the bowl of shiny marbles.
After doing a little research online I’ve learnt that the water should be changed regularly to prevent mosquitoes from breeding there. Don’t add sugar or honey to the water, not good for the bees.