Provided are plant hormone-based growth-enhancing compositions, which comprise at least one auxin, at least one cytokinin, and at least one polyaspartic acid, and which optionally comprise at least one seaweed concentrate and at least one surfactant. Also provided are methods of propagating grass plants, including those of family Poaceae, such as the sterile grass plant Arundo donax, by treating the mature or immature stems of these plants with growth-enhancing compositions to stimulate the development of roots and shoots from meristematic tissues.
