From what I've read, the most important thing you can do for bees, is to have plants they like throughout the growing season. Since we're in different zones, not everything may apply, but in our area, hyacinths seem to be popular in the spring, as are apple and plum trees. Lavender and spearmint are always a big draw and mine seem to love any rose they can fit into :)

Alyssum, stock and cosmos are all getting some notice right now, and butterfly bushes and coneflowers were popular in the later summer. Sunflowers, marigolds and zinnias seem to keep them happy in the vegetable garden. As long as there is something for them all spring/summer, they should stay around and come back next year.

Bees live somewhere...in someone's yard, in a tree in the woods on the side of the road...all kinds of places.

If you want bees to stay in your garden year after year, your best bet is to establish your own population of them.

Mason bees are pretty easy, but they're only active for a couple of months. If youw ant to see bees in your yard all summer long, then check out getting started with some honeybees.

If you don't want to manage your own population, then just plant a lot of bee-friendly flowers (types that provide both nectar AND pollen) and hope for the best. :-)