Phragmites australis in the Zhalong wetlands can not only form large areas of mono-dominant communities, but also form different community patches. By using large sample sizes and statistical analysis, a comparative study was performed on the height and biomass of ramets of P. australis populations in aquatic, wet, xeric, and saline-alkali habitats in wetlands. The results showed that in these four habitats, from June to October, the height and biomass of ramets of P. australis population were the highest in the aquatic habitat, and the lowest in the saline-alkali habitat; the height of ramets in the aquatic habitat was 1.5-2.3 times higher than that in the saline-alkali habitat; and the biomass of ramets in the aquatic habitat was 2.0-5.1 times larger than that in the saline-alkali habitat, while the difference and different orders among habitats were relatively stable. In the four habitats, the coefficients of variance in ramet height (19.45%-31.56%) among habitats were higher than those within habitats (8.07%-17.61%). The ramet height had a greater plasticity among habitats, while the coefficients of variance in ramet biomass (33.43%-5.61%) among the aquatic, wet, and saline-alkali habitats were lower than those within the habitats (44.85%-79.82%). Additionally, the ramet biomass had a greater plasticity within habitats. The ramets of P. australis populations in different habitats had great morphological plasticity in growth and production, showing obvious environmental effects, in which the soil moisture was the main positive driving factor (R > 0.80) of plasticity variation.