This experiment measured plant growth of a halophyte (species adapted to saline conditions) confetti tree (M aytenus senegalensis) using runoff from kneeholy plants (R uscus aculeatus). Three irrigation treatments were used, a standard nutrient solution or control (T0), runoff water collected from kneeholy plants irrigated with the standard nutrient solution blended 50:50 with tap water (T1), and 100% runoff water collected from kneeholy plants irrigated with the standard nutrient solution (T2), in which the nutrient concentrations were analyzed by high-performance liquid chromatography. Growth, photosynthetic parameters, and mineral composition were measured at the end of the experiment. Electrical conductivity and pH increased with increasing runoff application (decreased blending). Treatment 2 had significantly higher plant height, number of branches, number of leaves, leaf area index, and dry weight. Treatments 1 and 2 had significantly lower root lengths compared with the control. Chlorophyll concentration and green index color in leaves were greater in T2 and T1 than T0. The mineral composition of roots and leaves was affected by irrigation treatment, resulting in an increase of sodium and chloride concentration and a decline of nitrogen and phosphorous concentration compared with the control. The reuse of runoff water was beneficial for growing this commercially important halophytic species in Spain, a consideration that is particularly relevant in locations with water quality, quantity issues, or both.