The pom pom pine (Pinus sylvestris “pom pom”) is a dwarf, ornamental cultivar of Scotch pine (Pinus sylvestris) that lends itself to pruning its branches and needles into round balls on the ends that look like pom poms. This is is called topiary pruning and needs to be done every spring to maintain the pom poms' clean round form. Grown in U.S. Department of Agriculture plant hardiness zones 3 through 8a, pom pom pines pruned in this way make a striking addition to a landscape.
As the growing season begins, light green growth will appear on the outside of the dark green pom poms. If you trim the pom poms at this stage, you will bruise the foliage and leave an unsightly mess. In about mid-June, depending on the weather, the leaves will turn hard and leathery. This is the time to trim the pom poms for a smooth, round exterior.
The Pruning Guide
A circular guide of stiff wire is typically used as a guide for trimming pom poms. The guide is made to your desired size by wrapping the wire around a bucket, barrel, waste basket or other circular object. The goal is to remove the shaggy growth left from the previous growing season so the pom poms will retain their smooth spherical shape. The wire circle should be slightly smaller than the growth you want to remove. Using the same diameter of circular wire guide year after year will maintain the pom poms in the same size.
Pruning requires the gardener to stand above the plant with a hand-held hedge trimmer in one hand and the circular wire guide in the other. As the wire circle is moved around the plant, anything growing outside of the wire is trimmed. Done carefully, this topiary pruning, a kind of foliage haircut, will result in perfectly round, smooth pom poms.
To leave a nice, clean finish on your pom poms, step back periodically to see how you’re doing. If you cut too deeply, you’ll spoil the circular shape of your pom poms and the only way to restore the round shape is to make the pom pom smaller. A pom pom pine will grow to about 15 feet high and 10 feet wide, so you may want prune it to limit its vertical growth, making the pom poms more accessible for maintenance pruning.
Other Evergreen Pom Pom Trees
If you want an evergreen pom pom in your landscape, but live in warmer USDA zone than 8a, the sea green juniper (Juniperus chinensis “Sea Green”) is a good choice. The green columnar juniper (Juniperus chinensis “Hetzii Columnaris”) that grows through USDA zone 9, also lends itself to pom pom topiary shaping.
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