Biological invasions have contributed to biodiversity loss, ecosystem degradation, and impairment of ecosystem services worldwide, requiring actions towards their prevention and control. Since human and monetary resources are both limited in most countries, priorities must be settled in the real world of biological invasion prevention and control. To support the decision making process regarding plant species already introduced, we propose a classification key, based upon biogeographical and ecological attributes of the target plant population. The key shall be applied to a particular biogeographical region, based on the premise that a species never invades two distinct ecosystems in the same way. The key categorizes the species according to the potential threats offered to the native biodiversity and ecosystem services in that region. Management strategies are recommended on the basis of both the species performance as invader and its economic importance in the region. We highlight the importance of ecological studies to categorize a species by the threats it offers to a specific ecological region, in order to avoid the waste of efforts and resources with non-risky species. Eradication experiments are equally important to find ecologically, technically and economically viable solutions for the problems derived from biological invasions.