Pruning pines to maintain size and shape requires a specific method distinct from trimming deciduous shrubs. The term “pine bushes” typically refers to dwarf varieties, such as Mugo pines, or young pines cultivated to remain shrub-like. Because pines grow differently than other plants, improper trimming can cause permanent damage, leaving behind bare sections that will not regenerate with foliage. Understanding the unique biology of these evergreen conifers is the first step to successful pruning.
When and What You Need to Get Started
The optimal time to trim pine shrubs is in the late spring or early summer, determined by the plant’s growth cycle, not the calendar date. Pruning must occur when the new growth, known as “candles,” has fully extended but before the needles fully unfurl and harden into mature wood. Pruning too late in the season risks preventing the formation of next year’s growth buds, which can cause sections of the branch to die back.
Before starting, gather a few tools for a clean, efficient job. Sharp bypass hand pruners or shears are useful for cutting the candles, though many prefer to use their fingertips to snap off the soft growth. Always wear gardening gloves to protect your hands from sticky pine pitch and sharp needles. Safety glasses are recommended to shield your eyes from debris.
The Unique Rules for Trimming Pine Bushes
Pines have a biological limitation that makes their pruning method different from most other shrubs: they do not possess dormant buds on old, leafless wood. Cutting back into a section of a branch that only has brown, older needles or no needles will leave a permanent bald spot. The primary technique for managing pine size and promoting density is called “candling,” focusing entirely on the new spring growth.
The “candles” are the soft, upright, light-colored growth tips that emerge at the end of the branches. Candles consist of a central, dominant shoot surrounded by several smaller side shoots. To control the plant’s size and encourage denser foliage, you must reduce the length of these candles. The guideline is to remove no more than one-half to two-thirds of the candle’s total length.
This reduction shortens the current year’s growth and redirects energy into the remaining side buds, which develop into new, shorter branches. For a more compact appearance, the candles can be snapped off by hand while they are still tender, resulting in a softer, less-cut look to the remaining needles. The pruned candle will not grow further until the following spring.
Maintaining Size and Shape
Applying the candling technique allows for specific control over the shrub’s overall size and density. To reduce the plant’s size, selectively cut back the longest candles across the entire bush, focusing on those that extend beyond the desired profile. To achieve a denser, more compact shrub, the goal is to cut all the candles evenly across the plant’s surface, which encourages a uniform fullness.
When shaping a pine shrub, ensure the base remains slightly wider than the top, creating a slight taper. This wider profile is important because it allows sunlight to reach the lower branches, preventing them from becoming shaded out and dying back. If the top of the shrub is allowed to flare out, the lower foliage will thin out and leave a bare, woody bottom.
After the spring candle pruning is complete, inspect the shrub for any dead, damaged, or diseased wood. These branches should be removed completely with clean cuts back to a healthy branch or the main trunk. Removing this unhealthy material helps maintain the plant’s vigor and overall appearance.