The Philadelphus mock orange or Philadelphus coronarius is also known as sweet mock orange and fragrant mock orange. It is a deciduous, flowering, rounded shrub that can grow to a height of from 10 to 12 feet, and a width of 8 to 10 feet. Its fragrant white blossoms appear in late spring or early summer. The Philadelphus mock orange is used as a specimen planting or hedge/privacy screen in landscape design. Pruning is an important part of the care of this shrub and involves removing old growth, thinning out new shoots, and managing growth to suit your landscape design.
Do all pruning and shaping after the shrub has finished flowering. On a mature Philadelphus mock orange plant you should prune away approximately one-third of the old growth; this encourages new growth and will create a healthier shrub. Look for spots where the branches have become extremely dense. Using your hand pruning shears cut the branches back to a healthy bud. When you cut back close to a new bud the shrub will develop new growth at that cutting point. Pruning out the old wood will allow more sunlight in as well as improve air circulation. Do not prune a newly planted shrub–wait until after the second year to do any pruning.
Cut back out any new shoots at the base of the plant (you will use your hand pruning shears for this). Use your judgment as to what shoots you will prune out, leaving only those that will give the bush a pleasing shape. You can also thin the shrub by cutting some branches back to where they are attached to another main branch, or to where they are attached to the trunk. Depending upon the diameter of the branch you will either use your hand pruning shears or lopping shears; higher branches will require using the pole pruning shears.
View your shrub from all angles to determine if you need to prune any scraggly branches. Also look for branches that are encroaching upon other plants. Cut them off above a healthy bud. Depending upon the location of the branch or branches you will either use your hand pruning shears or the pole pruner.