The potential growth and biomass productivity of Miscanthus x giganteus was investigated under constraint-free conditions during two years with appreciable different climatic conditions in central Greece, and under three different plant densities (0.66, 1, 2 pl m(-2)) and two different nitrogen dressings (N-0 = 50, N-1 = 100 kg N ha(-1)). The field experimental design was a 3 x 2 factorial split plot in four blocks. Plant height, tiller number, leaf area index and dry weight per plant component were measured in subsequent harvests throughout the growing periods of 2001 and 2002. It was found that fertilisation within the studied rates did not affect growth and biomass productivity of the crop, and no interaction between fertilization and plant density was observed in any of the samplings. Contrary to fertilization, a significant effect of plant density was found, with the denser populated plants (10,000-20,000pl ha(-1)) performing growth rates of 250-350kg ha(-1) d(-1) for large parts of the growing period, reaching maximum dry biomass yields in excess of 38t ha(-1) in the more favorable year, 2002, and 28 tha(-1) in the warmer and drier year 2001. Such high yield potentials were explained by the particularly great assimilation rates of this crop that were also measured under light saturation and optimum temperature and water regimes. With such biomass yields (11.2-15.2 t ha(-1) oil equivalent), obtainable particularly under modest fertilisation needs, Miscanthus sinensis should be considered as a very promising crop for biomass production in Greece in the near future. (c) 2006 Elsevier Ltd. All rights reserved.