This thesis focuses on the observation and documentation of the root development of purple willow-cuttings (salix purpurea) in quartz sand, covering the following grain sizes: 0 - 1 mm, 0 - 4 mm, 0,1 - 0,3 mm, 0,3 - 1 mm and 0,5 - 2 mm. The studies have been conducted from 2014 to 2015 with 30 rhizotrones (six rhizotrones per grain size, three months each) in the experimental garden "Essling" of the University of Natural Resources and Life Sciences in Vienna. The root development has been evaluated through image analysis by a non-destructive method (GiA Roots) on the one hand and through a destructive method (analysis of washed-out and scanned roots with the help of WinRhizo) on the other hand. Apart from image analysis, the evaluation of grain size distribution and the determination of the water holding capacity have been important factors in this survey. Visual differences in root development in the various rhizotrones could be observed after a few weeks only. Rhizotrones filled with grainsize 0,5 - 2 mm had significant lower root growth in depth and width than the roots in the other rhizotrones, but a greater number of branches. Though grain sizes from 0 - 1 mm, 0 - 4 mm and 0,1 - 0,3 mm had similar root systems, the best growth behaviour could be observed in grain size 0 - 1 mm. The different rooting parameters of the image analysis need to be considered along with grain size and water holding capacity. In conclusion it can be stated, that different grain size causes varying rooting parameters and that roots in rhizotrones with finer grain sizes (0 - 1 mm, 0 - 4 mm, 0,1 - 0,3 mm) show better growth in comparison to rhizotrones with bigger grain size.