China Girl holly (Ilex X "Mesog") is grown for its deep green color and its upright, dense form. Growing 7 to 10 feet tall and hardy in U.S. Department of Agriculture plant hardiness zones 5 to 9, this evergreen bears lovely red berries in late fall. While China Girl has no regular need for pruning, it will benefit from the occasional trim to maintain its shape.
Thin a dense canopy with handheld pruners or lopping shears by cutting several branches back to the trunk or a major branch union. Thin branches evenly around the tree, focusing on areas where the branching is particularly crowded. This allows light and air into the center of the tree, resulting in a fuller, deeper canopy. Do this winter or early spring, no later than a week or so after fresh growth starts to emerge.
Trim the odd branch here and there that sticks out beyond the others. Also cut away any other branches that don't contribute to a pleasing shape.
Remove dead and sickly branches any time you find them, cutting all the way to healthy growth or to the trunk. Always bag diseased plant parts and set them out for collection, rather than placing them on the compost pile.