Holly trees can be pruned any time during the growing season. Some varieties, such as English hollies (Ilex aquifolium) and Japanese holly (Ilex crenata), require a light pruning to encourage their natural shape; others, such as American hollies (Ilex opaca var. americana), may need little or no pruning at all. The best time for spring and summer pruning is when the foliage begins to turn yellow in late winter and early spring: this signals that it’s time to make cuts above ground level by cutting back on old stems and branches at soil level. This process helps rejuvenate dormant buds while allowing new growth from below ground to emerge through the wounds created by your cuttings work done in late winter/early springtime..