Rapid evolution contributes to plant invasion success. Previous studies have rarely considered the coevolution of multidimensional traits in invasive plants. We compared multiple traits related to growth, fecundity, and herbivore palatability of the widespread invader Spartina alterniflora in its native (US) and introduced (China) families across large geographic scales. Of 18 tested variables, ten revealed genetic-based differences between native and introduced ranges, and nine exhibited latitudinal clines within the introduced range. Introduced families compared to natives exhibited superior syndromes with larger growth, higher fecundity, and lower palatability, which were linked to provenance climates and could enhance plant competitiveness and spread. We conclude that within only 40 years since its introduction to China, Spartina has evolved an integrated ecological strategy to enhance invasiveness under climate selective pressure, making it the most successful invader along China’s coast. Our study underscores the importance of considering multivariate traits to understand plant invasion success.