Increasing drought frequency threatens forest functioning across Central Europe, yet the extent to which species mixtures buffer tree growth against climatic stress remains uncertain. We analysed 20-year radial growth (from 2002 to 2021) of Norway spruce (Picea abies), European beech (Fagus sylvatica) and European larch (Larix decidua) from middle-aged pure forest stands, two-species mixtures and three-species mixtures in the Drahanská vrchovina, Czech Republic. 3220 tree-ring widths from 161 trees were evaluated using a distribution-based framework that standardised annual increments relative to each tree’s realised growth potential (Q0.95). Ordered growth-performance categories were analysed in relation to species identity, mixture type, competition and growing space using cumulative link mixed models.,Species identity was the dominant predictor of long-term growth performance. Beech showed the highest probability of maintaining high relative growth, spruce had intermediate but site-dependent responses, and larch showed the weakest resilience, with frequent multi-year growth suppression. Contrary to our expectations, increasing mixture complexity within observed gradient and group of species did not consistently improve growth resilience: two-species mixtures tended to perform better, whereas three-species mixtures were associated with lower relative growth performance and greater temporal variability. Larch did not show improved relative growth performance when mixed with beech or spruce. These results suggest that species-specific growth responses may be more important than mixture complexity or individual-tree competition in determining long-term growth performance. Consequently, increasing tree-species richness alone may not ensure stable growth, highlighting the importance of species identity and mixture composition when designing mixed forests for future climatic conditions, characterised by more frequent and intense hot and dry periods.