Abstract Red willow, an economically important ornamental shrub in Iran, is characterized mainly by its red stems, making it a valuable ornamental plant in flower markets. This study aimed to investigate the efect of foliar application of methyl jasmonate (MeJA) and ascorbic acid on the morphological and biochemical characteristics of red willow. The experiment was conducted as a completely randomized design with two factors and three replications. Juvenile willow shrubs (3 to 4-year-old red) were cultivated in Hossein Abad village, Markazi province, Iran. The experimental treatments consisted of MeJA (0, 100 and 200 mgL−1) and ascorbic acid (0, 100 and 200 mgL−1). Several traits were evaluated such as the longest branch and two nearest heights, total shrub diameter, the longest branch diameter (at lower, middle and upper parts), total anthocyanin content of the longest branch, salicin content, leaf chlorophyll (a, b and a+b) content, and carotenoid content. In addition, the number, length and width of leaves from the longest branch, fresh and dry weight of branches were analyzed. Results revealed that the application of MeJA and ascorbic acid signifcantly increased growth characteristics (height, leaf number, total shrub diameter, branch diameter, fresh and dry weight and total anthocyanin content) of red willow shrubs. Furthermore, it was found that 200 mgL−1 treatments of these two substances produced the best results. Red willow shrub growth parameters and yield were also improved by the interaction of these two factors. Additionally, a signifcant correlation was found between total anthocyanin content and leaf number of the longest branch, total shrub diameter, the height of nearest branch 2 and the plant fresh weight.
