The aim of this study was to determine the environmental conditions, individual architectures, and photosynthetic efficiencies of three sundew species:Drosera rotundifolia,D. anglica, andD. intermedia, found in well-preserved peatlands and sandy lake shores in NW Poland. Morphological traits and chlorophyllafluorescence (Fv/Fm) were measured in 581 individuals ofDrosera.D. anglicaoccupies the best-lit and warmest habitats, and also those that are the most heavily hydrated and the richest in organic matter; its rosettes are larger under conditions of higher pH, less organic matter, and less well-lit habitats.D. intermediaoccupies substrates with the highest pH but the lowest conductivity, the poorest level of organic matter, and the least hydration. It is highly variable in terms of individual architecture.D. rotundifoliaoccupies habitats that are the most diverse, and that are often poorly lit, with the lowest pH but the highest conductivity. It is the least variable in terms of individual architecture. The value of the Fv/Fm ratio inDroserais low (0.616 ± 0.137). The highest photosynthetic efficiency is achieved byD. rotundifolia(0.677 ± 0.111). It is significant for all substrates, indicating its high phenotypic plasticity. The other species have lower and similar Fv/Fm values (D. intermedia, 0.571 ± 0.118;D. anglica, 0.543 ± 0.154). Due to its very low photosynthetic efficiency,D. anglicaavoids competition by occupying highly hydrated habitats.D. intermediahas adapted to the occupation of highly variable habitats in terms of hydration, whileD. rotundifoliais primarily adapted to variable light conditions.