Local adaptation of plant flower and life-history characters has often been studied in the context of specialized pollinators that vary in frequency or behavior among sites. Recently, the potential importance of herbivores and the interactions of pollinators and herbivores have also been recognized. We studied pollinators, herbivores, and plant phenotypes in four populations of the western wallflower (Erysimum capitatum, Brassicaceae) along an elevational gradient in the Front Range of the Eastern Slope of the Colorado Rocky Mountains in 2005 and 2006. Several phenotypic characters varied among populations over a small spatial scale (<50km), and plants were visited by a wide variety of pollinators and herbivores. E. capitatum plants in these populations were primarily pollinated by bees, pollen beetles, and flies. The most common types of pollinating visitors differed among populations. Ants were the most common visitors in all populations. They removed nectar from the base of flowers, occasionally attacked bees, and rarely came into contact with stigmas. Many other herbivores fed on flowers and buds of E. capitatum. Some of these damaged petals, potentially making plants less attractive to pollinators. Gall midge larvae (Cecidomyiidae) formed galls from flower buds and typically prevented flowers from opening. Both herbivores and pollinators were different from year to year and from population to population. We argue that the potential for local adaptation to pollinators and herbivores exists in Erysimum capitatum.