The Podocarpus is a popular choice for many landscapes, particularly in warmer regions. This evergreen conifer is highly valued for its dense, deep-green foliage, making it an excellent option for hedges, screens, and specimen trees. Its natural growth habit is typically narrow and upright, which makes it attractive for privacy barriers that do not take up excessive space. When homeowners seek to limit the height of this fast-growing species, the question of whether to “top” the tree frequently arises.
Understanding the Practice of Tree Topping
Tree topping is a destructive pruning practice involving the indiscriminate cutting of large branches and main leaders to blunt stubs. This method is employed to quickly reduce the tree’s overall height or canopy size. The topping cut creates a large, open wound that the tree cannot easily seal off, leaving the internal wood exposed and vulnerable.
The immediate biological response is intense stress, as the tree loses photosynthetic capacity. To compensate, the tree rapidly produces numerous weak, upright shoots just below the cut. These sprouts are weakly attached to the decaying wood, leading to a structurally unsound and hazardous canopy. The resulting dense growth also shades out lower branches, causing interior dieback and reducing the tree’s overall health.
Specific Harm Topping Inflicts on Podocarpus
Podocarpus trees react particularly poorly to the massive wounds inflicted by topping cuts. Like all trees, Podocarpus uses compartmentalization to isolate damaged tissue and prevent decay. However, when a large branch is topped, the tree’s defensive walls are overwhelmed, and the wound often fails to close completely.
The open wounds provide direct entry points for wood-decaying fungi and insects into the tree’s core. This leads to internal rot that compromises the structural integrity of the main trunk and limbs. The dense flush of water sprouts that follows topping ruins the Podocarpus’s natural form, creating a distorted, bushy top. These new shoots are prone to snapping because they sprout from damaged, decaying wood rather than from a strong branch collar.
Proper Pruning and Size Management Techniques
Size management for Podocarpus should focus on proper pruning techniques that respect the tree’s biology. For height reduction on specimen trees, the appropriate method is the use of “reduction cuts.” This involves cutting a long branch back to a smaller, healthy lateral branch that is at least one-third the diameter of the removed limb. This technique transfers growth to the lateral branch, maintaining a natural appearance and allowing the tree to seal the smaller wound effectively.
Shearing for Hedges
When Podocarpus is maintained as a formal hedge, regular light shearing of the new growth tips is the preferred technique. This encourages a dense, bushy exterior while keeping the tree at a desired height and width. Removing only the soft, young growth, ideally in late spring or early summer, minimizes the severity of the wounds and stimulates back-budding for a fuller look.
Thinning
“Thinning” is another valuable technique, where entire branches are selectively removed back to the trunk or a main branch. This helps to improve light penetration and air circulation within the canopy.