Penn State Master Gardener Practice Exam

Root cuttings succeed best when taken during dormancy because the roots are storing energy in the form of carbohydrates. In this period, the plant has slowed or stopped above‑ground growth, so carbohydrates accumulate in the root system rather than being used for new shoots. Those stored reserves provide the energy needed to initiate rooting and to push the new plant’s first growth once the cutting is planted, increasing the chances of success. If you cut during the active growing season, the plant is already directing energy to new leaves and stems, leaving less stored energy in the roots for the cutting to rely on, which can lead to poorer rooting results. The presence of mature leaves or flowering isn't the key factor here; the essential condition is a large carbohydrate supply in the roots during dormancy.