The experiment aims was to study the influences of the mother bulb weight on the growth and development, of the plants of ornamental onion. The study was conducted during October 2015 – June 2016 and the biologic material was represented by Allium ‘Purple Rain’. The bulbs were divided in three different weight groups: W1 (15.1-30 g), W2 (5.1-15 g), W3 (< 5 g), which were reprezented the three variants (V1, V2, respectively V3). The bulbs were planted in the field and the plants were studied thrue the biometric determinations. The results were compared with the average of the experiment. The research showed that the all the analyzed characters (number and length of leaves, number and weight of new formed bulbs, flowers yield, diameter of the inflorescence) were decreasing from V1 to the V3 variant. The highest number of the flowering plants (98.9 %) was resulted from V1 variant. From V2, bloomed only 20% of the bulbs and from V3 the bulbs did not got flowers. The flowering time was earlier for the plants resulted from the biggest bulbs (V1), with around 3 days, then the V2 and around 7 days then V3. The capacity to form new bulbs, expressed in bulb number or bulb weight per plant, was increased with the increasing of the mother bulb weight. The number of leaves per plant and the length of the leaves were higher for V1, as against the other two variants