Our Nation's national grasslands represent large tracts of native prairie that pose distinctive challenges to studying and managing invasive plants. Because newlyintroduced species can quickly spread unimpeded across large areas of these uninterrupted landscapes, early detection and rapid response are critical components of invasive plant research and management. However, few studies focus specifically on recently introduced exotic plants in the early stages of establishment. Documenting the pattern of invasion before the species becomes widespread helps identify traits that may contribute to understanding the success of recent invaders, and increases our knowledge of the factors influencing invasibility. Forest Service scientists and partners developed an aggressive approach to investigate the biological and habitat characteristics of sickleweed (Falcaria vulgaris), a rapidly expanding invasive plant newly introduced into the grasslands of the Northern Great Plains. The approach uses herbarium records of sickleweed to reconstruct the introduction history and potential pathways of spread. Using detailedfield surveys, researchers described the pattern of abundance and distribution of the species and identified the factors that can predict the susceptibility of local and regional grassland communities to invasion. Cutting edge laboratory research on population genetics and seed germination and establishment characteristics of sickleweed complements this work. Genetic analyses identified the number and location of potential sites of introductions, while seed germination trials described the establishment and spread potential of the species. Collectively, these studies help managers develop a range of management alternatives that reduce establishment of new populations and limit expansion of existing populations. The approach also provides a template for future evaluations of newly introduced species before they potentially become invasive.