In the framework of variety testing, evaluation of the flower of Begonia x tuberhybrida Voss. is done by experts. The colours of the flowers are compared with the RHS colour chart. For each flower colour a code is given. This method has several disadvantages (data cannot be statistically analyzed with standard ANOVA techniques, bias by the expert is possible, difficult measurement depending on the light environment, ...) that can be overcome with image analysis. In this study several parameters were tested to distinguish the different varieties. Varieties were split in different colour groups (white, red and yellow-orange) and parameters were analyzed. Parameters based on the green colour plain of the RGB colour space resulted in the largest discriminating power. Parameters based on the HSV colour space performed less well.