They seem to love any of the cole crops that you let go to flower (broccoli, cauliflower, mustard, anything in that family). They also love Borage. LOVE it! I started planting Borage in my potager style vegetable garden a few years ago. It's easy to grow (sometimes too easy, as it self-seeds prodigiously), it's really pretty, has companion effects for other plants, and the young leaves are edible or can be made into tea. In late summer, when the plants are each 2-3' high and just as wide, they are COVERED with light blue flowers that the bees love. They also seem to love mint and oregano flowers too.