While the precautionary principle advocates a proactive posture towards the eradication of invasive species, there is little empirical evidence to support this effort. By examining fennel management on Santa Cruz Island, California, from three perspectives, I advocate an ecological framework for weed management. First, a critical discourse analysis revealed that underlying scientific assumptions and personal bias failed to provide hypothesized results. Next, two long-term field studies, The Nature Conservancy's Central Valley Fennel Removal Experiment and the University of California at Santa Cruz's Natural History Field Quarter Fennel Project, focused on the response of vegetation guilds of introduced and native origin to restoration disturbances that produced results contrary to common wisdom. Finally, the allelopathic potential of fennel was evaluated against a suite of species from introduced and native origin. Allelopathic interference was most negative for growth of introduced species with little significance for their germination, and interference was most negative for germination of native species with little significance for their growth.