Putting some water out for Solitary, Mason and Pollen Bees really helps the bees. Put the water near the bee nests; a shallow container with a couple of rocks for the bees to land on is perfect. Put in fresh water every couple of days. They'll use the water to make the mud they need for their nests, too.
Honey bees love borage! Flowers are edible for humans and taste like cucumber. It provides high quality, nutritious BLUE pollen. The nutritional benefits of this pollen may help honey bees fight disease. Self seeding annual needing well drained soil. Borage via Organic Magazine: The 11 Best Plants for Beneficial Borders
Solitary, Mason and Pollen Bees need water and exposed earth to make the mud that they use to build their nests. There are lots of ways to make sure your garden contains water for bees. A lovely stone with a natural dip will fill with rain water and you can keep it fresh on sunny days, too.