Hi Carla, if you are interested in pollinating fruit trees, mason bees will do the job quite nicely. Read through this publication from OSU Extension Service, "Nurturing Mason Bees in Your Backyard in Western Oregon". This is a thorough introduction to what one needs to know to have the highest possibility of success with mason bees.

You have the option of installing mason bee nesting blocks, planting flowers, then waiting to see if they find your landscape an attractive home. If you would rather purchase mason bees, many plant nurseries carry the bees and supplies in spring. Check out your local nurseries to see if they plan to have mason bees. The Home Orchard Society, which is based in Clackamas, Oregon, also carries mason bees and supplies.

Enjoy this very interesting new project.