Despite steep installation costs and the need for high technological levels, soilless culture techniques can improve rose crop productivity. However, when such techniques are used under Mediterranean climatic conditions, the result is high root respiratory activity, which can lead to a rapid drop in oxygen levels and affect root morphology and function, thus having a negative effect on production and final quality. We grew roses to study both the effect of intermittent oxygen supply on the root media by applying the nutrient solution supersaturated with oxygen (technique called oxyfertigation) and the substrate particle size. Root hydraulic conductivity, aerial biomass and leaf of roses for cut-flower production grown in two kinds of perlite (fine-grade and coarse-grade) were assessed. The data indicated a great deal of variability in the parameters of root hydraulic conductivity (Lr) and specific hydraulic conductivity (Lre). Plants grown in fine-grade perlite had a significantly higher Lr and showed greater plant development. An upward trend was observed in Lr and Lre values in plants subjected to oxyfertigation treatments. Leaf-surface area and dry weight (leaves and flowers) was also greater in the plants that received oxyfertigation treatments, especially in those growing in the fine-grade substrate. Oxyfertigation may be favourable for use in substrates in situations where there is a risk of hypoxia.