Trimming pom poms involves pruning to form ball-shaped foliage at the end of tree or shrub branches, says Mike McGroarty from ICanGarden.com. It is a type of topiary practice where branches are trained to maintain an ornamental shape. It takes artistic visioning and patience to trim pom poms successfully, but once you persevere, the vegetative sculpture will make a fine addition to your front or back yard. It is also a way to rescue unappealing shrubbery. Donnan Landscape Services recommends you trim and form new pom shapes at the beginning of the summer.
Select a tree or shrub to trim. Wilson Bros. Nursery says it is best to work with small or mid-size shrubs that have both outward and upward-growing branches. Junipers are commonly used, including Japanese garden junipers and spreading junipers such as sea green and hetzi varieties. McGroarty adds that vertical juniper types, such as blue rug and green mound varieties, can be trimmed to form a tiered-pom pom effect. Other types of vegetation that may be used are privet shrubs, compacta holly shrubs, boxwood, pine and spruce. If you are first starting out, McGroarty recommends picking up cheap plants from the garden store on which to practice. Trees to Please suggests picking a tree that is blocking sunshine from entering your house or one that has several dead branches.
Visualise the pom shape you will create before you start trimming. Deduce which limbs you will need to remove from the trunk or main branches and which should be trimmed to form a spherical shape on the ends of these main branches.
Start trimming the interior growth of the shrub. Prune branchlets (the secondary twigs connected to the main branches), starting at the bottom of the main branch. When pruning, make sure to leave at least 6 to 8 inches of foliage at the top end of each branch. Do not cut any main exterior branches yet.
Step back and look at the shrub once you have trimmed the interior. Decide which branches you would like to keep. Cut the other branches.
Trim the foliage you left on the end of each branch. Form a pom or ball-shape. Do this slowly, continually stepping back to determine your next cut. If you want a variety of shapes, Wilson Bros. encourages creativity, such as saucer, oval and square-shaped topiaries.
Continue tending to your shrub sculpture throughout the months by pruning twigs and branches that alter the pom form. It can take a year or more for your shrub to be trained and have the appearance you desire.