In this study, phytosociological plots are used to describe species composition and ecological conditions of habitats in which Solidago × niederederi, a natural hybrid between the North American S. canadensis and the European S. virgaurea, was found as established in Poland. Four groups of phytosociological plots have been distinguished based on the unweighted pair group method with arithmetic mean. The groups did not differ significantly in the mean number of species per plot and in the species evenness, in contrast to the mean values of Shannon-Wiener index and Simpson index. In each group of phytosociological plots, S. ×niederederi and S. virgaurea had the highest value of constancy degree. Meadow species of the class Molinio-Arrhenatheretea had the highest share in all groups of phytosociological plots. Considering the Ellenberg’s indicators, the groups of phytosociological plots differed significantly in the mean values of the light and thermal conditions, soil moisture, soil reaction, and nutrients. The results suggested that S. ×niederederi can be established in well light places with partial shade and temperate conditions, on moist, moderately acidic to almost neutral soils with average fertility and is strongly associated with S. virgaurea and meadow species of Molinio-Arrhenatheretea.