Knowledge from ecological sciences is an important reference for landscape design as Urban Green Spaces (UGS) play a critical role in the ecological protection of cities. There is an ongoing debate among ecologists on the value of exotic vegetation to ecosystem resilience and integrity, with authors arguing that in order for ecosystems to survive in future climates, exotic species with similar conditions in their current range must be considered. Others deem biodiversity vital for ecosystem functions and services, stating that most biodiversity losses are man-induced and should be addressed through the enhancement of native communities. Through a literature review, we confronted the arguments used in this debate, with the aim of conducting a comprehensive analysis of the potential of exotic and native vegetation in different aspects of the vegetation’s performance. The outcomes are important for the assessment of vegetation assemblages within UGS projects. Despite the strong arguments regarding their performative and adaptive capacity, we conclude that exotics pose significant ecological risks and have multiple negative impacts on ecosystem processes. Natives not only present high adaptive capacity, but also provide additional benefits for biodiversity, ecosystem integrity, and for people. In a broader framework, the literature demonstrates a preference for the use of native species in most situations.