Holly (Ilex spp.) is an evergreen shrub that comes in hundreds of varieties. Species can range from 1 1/2 feet tall to up to 50 feet tall or more. Holly is best known for its shiny green foliage and red berries that often grace Christmas holiday table decorations. Holly is a hardy plant that requires little maintenance, but knowing when to prune holly helps to keep your shrub looking its best.
You can find types of holly shrub to fit many landscaping designs. They come in a variety of colors from dark green to blue-tinged as well as in variegated forms. Holly requires a site with good drainage and full sun exposure though it will also grow in partial shade. A slightly acidic soil enriched with organic matter helps your holly shrub to thrive. Berries grow on female plants, which require male plants to be in the area to produce the berries. Many varieties of holly bear thorns, but thornless varieties are also available.
Best Time to Prune
Timing the pruning of your holly shrub can be important to the health and appearance of the plant. Pruning causes the plant to send out new growth, which is easily damaged by sudden drops in temperature and frosts. Early summer is the best time to prune holly. Though holly generally has an attractive, natural shape, it requires removal of dead, broken and wayward branches. Thinning of interior branches also allows better light and air circulation for a healthy plant.
Deciduous varieties of holly require more severe pruning each year than evergreen types. Prune stems thicker than your thumb down to one-third of their length to encourage new growth. Remove old canes and shape to conform to the natural form the shrub. Remove heavily intersecting branches that restrict airflow and those that appear weak. Cut back diseased branches to healthy wood. Prune evergreen varieties to conform to general shape and to remove dead or diseased branches. Always ensure tool blades are properly sharpened before pruning.
Excessive pruning reduces the amount of fruiting that occurs that year. Only prune after all danger of frost has passed. To repair storm damage, remove broken branches and shape the plant to its original form as much as possible. Removing branches for decorations during the Christmas season will not damage the plant if it is not trimmed radically.