Technical Abstract: Flowering plants in agricultural landscapes can provide ecological services, such as nectar-food for adult parasitic Hymenoptera. Various native, introduced/established and cultivated potted plants-in-flower were used to bait interception traps along the wooded margins of fields planted seasonally with either feed-corn or rye. Depending on circumstances, controls consisted of traps baited with the same species of plant without flowers, a pot/area without plants or both. In most cases pots were rotated among trap-sites. Of the 19 plant species tested, 10 captured significantly more summed ichneumonoids and chalcidoids, 7 more Braconidae, 2 more Ichneumonidae and 6 more Chalcidoidea. Among Braconidae, traps baited with certain plants captured significantly more of specific subfamilies. “Attractive” and “unattractive” plant species tended to cluster in a principal components vector space constructed from plant morphological characteristics (flower width, flower depth, flower density and plant height). Flower width and plant floral-area (flower width2 * flower density) were the variables that most often explained the variance in capture of the different parasitoid taxa. The present study identified particular plants that could be incorporated into regional conservation biological control programs and suggested what characteristics might help identify other candidates for agricultural landscape modification.