Objective  To explore the method for safely controlling Praxelis clematidea, one of the most invasive plant in South China, and study the potential of Pennisetum hydridum to compete with and replace Praxelis clematidea.

Method  Pot experiment with a series of planting ratios of Pennisetum hydridum and Praxelis clematidea was conducted. Competitive indices and morphological traits of two plant species were measured.

Result  Competitive balance indices of Praxelis clematidea ranged from −0.97 to −0.40, lower than zero in all treatments with different planting ratios, indicating Pennisetum hydridum had a competitive dominance. The biomass per plant of Pennisetum hydridum increased from 48.98 g to 161.66 g with increasing ratio of planted Praxelis clematidea. Mixing two plant species suppressed growth and development of stem and leaf for Praxelis clematidea, and resulted in that total leaf area, total stem length and branch number per plant of Praxelis clematidea decreased by 43.4%−68.2%, 49.4%−63.6% and 46.1%−71.6% respectively compared with those in monoculture of Praxelis clematidea.

Conclusion  Pennisetum hydridum has competitive inhibition against Praxelis clematidea. It is a prospective candidate to control and replace Praxelis clematidea.