Social bees have been widely used as model systems for studying learning and memory. Much less is known about these phenomena in solitary bees, in spite of the fact that most bee species of the world are solitary. We explore the ability of the solitary blue orchard bee, Osmia lignaria Say, to learn and remember information when foraging. First we tested innate flower color preference using blue and white flower patches, and yellow and blue flower patches. The blue orchard bees showed a marked color preference for blue flowers in blue-white as well as in blue-yellow flower patches, even though all flowers provided the same reward. However, when white flowers offered the greater reward (either quality/molarity or quantity/volume) in blue-white dimorphic floral patches, the preference for blue readily decreased, which was not observed in control bees. Learning occurred more rapidly when a difference in reward volume rather than reward molarity was used. These results were approximately the same for males as for female bees. The information learned about flowers was retained for at least three hours.