Masons in the Garden
The orchard mason bee (Osmia lignaria) is among more than 3,500 species of native North American bees that pollinate wild plants, commercial crops and gardens. Between 250 and 750 orchard mason bees can pollinate an entire acre of apples. This bee, also called the blue orchard bee because of its dark blue color, is a bit smaller than a honeybee. Because they don't work cooperatively in hives, masons are among the "solitary bees" (though they don't mind nesting close to others of their species).
Orchard mason bees look for natural cavities like hollow stems and insect holes in which to nest--they do no excavation of their own. Orchard mason bees are easy to attract by drilling holes of proper sizes in wooden blocks. You can also buy special paper straws or tubes and ready-made housing from beekeeping suppliers. The bees are gentle, beneficial and fun to observe. The overwintering adults emerge in early spring--March or April, in these parts--to mate and collect pollen and nectar to provision their nests, which they seal with mud. They do their work quickly--over a period of about four to six weeks--after which the adults die. The young develop and mature within the nests and emerge the following spring. For "nest block" construction plans and other instructions for raising and managing orchard mason bees, visit www.ces.ncsu.edu/depts/ent/notes/Other/note109/note109.html. Another good resource can be found at www.attra.org/attra-pub/nativebee.html.