Pruning greene's mountain ash stimulates vigorous growth by removing dead or diseased wood, enhancing air circulation, and allowing more light to reach the inner branches. It also maintains the desired shape and size, adding to the plant's aesthetic appeal.

Pruning greene's mountain ash during late winter or early spring is ideal as this timing allows for rapid healing of cuts before new growth starts. In late winter, the plant is dormant, which minimizes stress and reduces the risk of disease infection at the cut sites. Early spring pruning should be done before the sap starts flowing, to avoid weakening the plant. Additionally, since greene's mountain ash flowers on old wood, pruning after bloom could remove the developing fruit. Pruning in late winter ensures that blossoms and subsequent fruit production are not negatively affected. Regular pruning during these recommended seasons helps maintain the plant's shape, promotes healthy growth, and enhances fruiting.