Schoenoplectus californicus (C.A. Meyer), Soják is one of the plants most used to treat wastewater in a constructed wetland. Our objective is to study the growth and nutrient uptake of Schoenoplectus californicus Cyperaceae in a constructed wetland fed with swine slurry. The methodology used to evaluate the growth of the Schoeno-plectus californicus Cyperaceae was to evaluate the allometric, relative abundance and biomass of the plants in the period 2009 - 2010. The results show that Schoenoplectus californicus had allometric growth between 31.2 to 98.4 and relative abundance between 21 to 108 individuals m-2, during the fall and spring seasons, respectively. These results are influenced by the nitrogen content (between 0.05 to 2.0 kg N ha-1 d-1) present in the constructed wetland. In this same period, the increase in Schoenoplectus californicus biomass (~28%) is related to a decrease in nitrogen loading between 2.0 to 0.05 kg N ha-1 d-1. Aboveground biomass was greater (500 to 724 g m-2) than belowground biomass (4.8 to 22.7 g m-2). Due to nutrient translocation in spring-summer, the N:P ratio aboveground ranged from 9 to 16, while belowground the ratio varied from 7 to 10.