The trend of increasing demand for wood raw material is becoming of great global concern. Fast-growing plantations, such as those of Paulownia, are being established in different parts of the world, as a viable alternative to quickly produce quality wood at competitive costs. The presence and proportion of juvenile wood directly influences the capacity and possibilities of industrial transformation for sawn timber, veneer or plywood for furniture, construction or packaging purposes. The objective of the research is to analyze the radial variation of physical and anatomical characteristics of Paulownia elongata x fortune hybrid Cotevisa 2 wood from fast-growing plantations. A sample of 14 trees from a seven-year-old plantation established in Valencia (Spain) with a planting frame of 4 m × 4 m was used. Although there is no data from subsequent rings to the 6th, the obtained results indicate that from the 5th year of growth, the wood of Paulownia elongata x fortunei Cotevisa 2 could stabilize in some key parameters such as the radial growth of the rings, the structure and proportion of the vessels, the structure of the cell wall, the density of the material and the behavior in terms of dimensional stability in the drying process. Thus, for practical purposes, we can indicate that the transition from juvenile wood to mature wood can begin from the 5th year of growth. Enlarging the rotation in few years reduces significantly the presence of juvenile wood and contributes to improve the roundwood quality for added-value solid wood products.