Pruning, the art and science of selectively removing plant parts, is essential for maintaining plant health, encouraging desired growth, and maximizing fruit or flower production. However, incorrect pruning techniques can inflict significant damage, leading to weakened plants, reduced yields, and even death. Understanding which pruning methods to avoid is just as crucial as knowing which ones to employ.
The Perils of “Topping”: A Pruning Practice to Shun
Topping, also known as heading, is the indiscriminate removal of the top portion of a tree or shrub. It’s perhaps the most damaging pruning practice and should be avoided at all costs. The rationale behind topping often stems from a desire to control a plant’s height quickly, reduce shade, or alleviate concerns about falling branches. However, the supposed benefits are far outweighed by the negative consequences.
Why Topping is Detrimental
Topping disrupts a plant’s natural growth habit. It eliminates the dominant terminal buds, which are responsible for apical dominance – the plant’s tendency to grow upward. Removing these buds triggers the growth of numerous lateral shoots just below the cut. This results in a dense cluster of weak, upright branches that are weakly attached to the main stem. These branches are often referred to as “water sprouts” or “suckers.”
Water sprouts grow rapidly, creating a dense canopy that blocks sunlight and reduces air circulation. This dense growth makes the plant more susceptible to pests and diseases. Furthermore, the weak attachments of these branches make them prone to breakage, especially during storms or under heavy snow loads.
Topping also creates large, open wounds that are slow to heal. These wounds provide entry points for insects, fungi, and other pathogens. The plant expends considerable energy trying to seal these wounds, diverting resources away from growth, flowering, and fruiting.
Ultimately, topping weakens the plant, reduces its lifespan, and compromises its aesthetic appeal. A topped tree or shrub will never regain its natural form and will require constant maintenance to control the unruly growth.
Alternatives to Topping
If height reduction is necessary, consider hiring a certified arborist to perform crown reduction pruning. This technique involves selectively removing branches throughout the crown of the tree, reducing its overall size without sacrificing its natural shape or health. Crown reduction requires skill and knowledge to ensure that the remaining branches are strong and healthy.
Choosing the right plant for the location is also crucial. Before planting, consider the plant’s mature size and growth habit. If the plant is likely to outgrow the space, select a smaller variety or a different species altogether.
Shearing: A Uniformity That Can Harm
Shearing involves using hedge trimmers or other tools to create a uniform, often unnatural shape. While shearing can be useful for maintaining formal hedges, it can be detrimental to other types of plants.
The Drawbacks of Shearing
Repeated shearing creates a dense outer layer of foliage that blocks sunlight from reaching the inner leaves. This can lead to the death of the inner foliage, resulting in a hollow, unattractive plant.
Shearing also stimulates dense, twiggy growth on the exterior of the plant. This dense growth can trap moisture and create a favorable environment for fungal diseases. Furthermore, the dense outer layer prevents air circulation, further increasing the risk of disease.
Shearing can also remove flower buds, reducing or eliminating flowering. Many plants produce flower buds on the previous year’s growth. Shearing these plants at the wrong time of year can remove the flower buds, resulting in a lack of blooms.
When Shearing is Acceptable
Shearing is generally acceptable for maintaining formal hedges, such as boxwood or yew. These plants tolerate shearing well and can be maintained in a formal shape with regular trimming.
However, even with formal hedges, it’s important to shear properly. Avoid shearing too deeply, and be sure to taper the sides of the hedge to allow sunlight to reach the lower branches.
Stub Cutting: Leaving Behind Unnecessary Wounds
Stub cutting refers to leaving a short stub of a branch or stem when pruning. This is a common mistake that can lead to several problems.
Why Stub Cutting is Problematic
Stubs are unsightly and serve no purpose. They eventually die and decay, creating entry points for insects and diseases. The decaying stub can also weaken the surrounding wood, making the branch more susceptible to breakage.
The plant will attempt to seal the wound created by the stub cut, but it will be unable to do so effectively. The exposed wood will remain vulnerable to infection and decay.
The Correct Pruning Cut
The correct pruning cut should be made just outside the branch collar. The branch collar is the slightly swollen area at the base of the branch where it joins the trunk. Cutting just outside the branch collar allows the plant to seal the wound properly.
The branch collar contains specialized cells that promote wound closure. When pruning, avoid cutting into the branch collar or flush with the trunk. This can damage the plant’s natural defense mechanisms and increase the risk of infection.
Lion’s Tailing: Stripping Away Inner Growth
Lion’s tailing involves removing all of the inner branches from a tree, leaving only a tuft of foliage at the ends of the branches, resembling a lion’s tail. This practice is often done to improve visibility or reduce wind resistance. However, it is detrimental to the tree’s health and should be avoided.
The Negative Effects of Lion’s Tailing
Lion’s tailing weakens the tree’s structure. The inner branches provide support and stability. Removing these branches makes the remaining branches more susceptible to breakage, especially during storms.
Lion’s tailing also reduces the tree’s ability to photosynthesize. The inner branches contribute significantly to the tree’s overall photosynthetic capacity. Removing these branches reduces the tree’s energy production, weakening it over time.
Furthermore, lion’s tailing exposes the inner branches to direct sunlight. The bark on these branches is not adapted to direct sunlight and can become sunburned. Sunburn can damage the bark and increase the risk of insect infestation and disease.
Proper Pruning for Wind Resistance
If wind resistance is a concern, consider thinning the crown of the tree. Thinning involves selectively removing branches throughout the crown, reducing the density of the foliage without sacrificing the tree’s overall structure or health. Thinning allows wind to pass through the crown more easily, reducing the risk of wind damage.
Leaving Hangers: The Danger of Broken Limbs
“Hangers” are broken branches or limbs that are partially attached to the tree but are hanging loosely. These branches pose a safety hazard and should be removed immediately.
The Risks of Hangers
Hangers are unstable and can fall at any time, potentially causing injury or property damage. They also create entry points for insects and diseases. The broken wood is vulnerable to infection and decay, which can spread to healthy parts of the tree.
Removing Hangers Safely
When removing a hanger, use proper pruning techniques to avoid further damage to the tree. Make a clean cut just outside the branch collar. If the hanger is large or heavy, use ropes or other supports to prevent it from falling unexpectedly.
Pruning at the Wrong Time: Timing is Everything
The timing of pruning can significantly impact a plant’s health and flowering potential. Pruning at the wrong time of year can stress the plant, reduce flowering, or increase the risk of disease.
General Pruning Guidelines
As a general rule, most deciduous trees and shrubs should be pruned during the dormant season, typically late winter or early spring before new growth begins. This allows the plant to heal quickly and redirect its energy into new growth.
Spring-flowering shrubs, such as azaleas and forsythias, should be pruned immediately after flowering. Pruning these shrubs during the dormant season will remove the flower buds, resulting in a lack of blooms.
Summer-flowering shrubs, such as butterfly bushes and crape myrtles, should be pruned in late winter or early spring. These shrubs bloom on new growth, so pruning them during the dormant season will encourage more flowering.
Evergreen trees and shrubs can be pruned at any time of year, but it’s best to avoid pruning during periods of extreme heat or drought.
Specific Timing Considerations
Consider the specific species and its flowering habits when determining the best time to prune. Research the plant’s specific needs to ensure that pruning is done at the optimal time.
Neglecting Sanitation: A Pathway to Disease
Proper sanitation is essential for preventing the spread of plant diseases. Failing to disinfect pruning tools or remove diseased plant material can inadvertently spread pathogens throughout the garden.
The Importance of Sanitation
Diseased plant material can harbor pathogens, such as fungi, bacteria, and viruses. These pathogens can be easily spread to healthy plants through contaminated pruning tools.
Sanitation Practices
Disinfect pruning tools before and after each use. Use a solution of 1 part bleach to 9 parts water or a commercial disinfectant designed for pruning tools.
Remove and dispose of diseased plant material properly. Do not compost diseased plant material, as this can spread the pathogens to other plants. Instead, burn or bury the diseased material.
Over-Pruning: Less is Often More
Over-pruning can stress the plant and reduce its vigor. It’s generally better to prune conservatively, removing only what is necessary.
The Dangers of Over-Pruning
Over-pruning can remove too much of the plant’s photosynthetic capacity, weakening it over time. It can also stimulate excessive growth of water sprouts, which can create a dense, unruly canopy.
Furthermore, over-pruning can disrupt the plant’s natural shape and balance. It can also make the plant more susceptible to insect infestation and disease.
Pruning with Restraint
When pruning, focus on removing dead, damaged, or diseased branches. Also, remove any branches that are crossing or rubbing against each other. Thin the crown of the plant to improve air circulation and sunlight penetration.
Avoid removing more than one-third of the plant’s foliage in a single pruning session. If more extensive pruning is necessary, spread it out over several years.
By understanding and avoiding these common pruning mistakes, you can help ensure the health, beauty, and longevity of your plants. Remember that proper pruning is an art and a science. With knowledge and practice, you can become a skilled pruner and create a thriving garden.
What is the most common pruning mistake people make?
Over-pruning is arguably the most frequent error. Novice gardeners, often eager to shape their plants or remove perceived deadwood, can drastically reduce a plant’s foliage. This hinders its ability to photosynthesize efficiently, weakening the plant and making it more susceptible to diseases and pests.
Excessive pruning stresses the plant, forcing it to expend valuable energy reserves to regrow lost foliage. This can lead to stunted growth, reduced flowering or fruiting, and in severe cases, even plant death. Always prune conservatively, removing only what is necessary and observing the plant’s response before making further cuts.
When is the worst time to prune flowering plants?
Pruning flowering plants at the wrong time of year can significantly impact their bloom production. Many plants develop flower buds on “old wood” (growth from the previous year). Pruning these plants in late winter or early spring, just before their bloom season, removes these precious buds, resulting in few or no flowers that year.
To avoid this disappointment, research your specific plant’s bloom cycle. Plants that bloom in spring should be pruned shortly after flowering. Those that bloom in summer or fall typically bloom on “new wood” (growth from the current year) and can be pruned in late winter or early spring before new growth begins.
What’s the danger of using dull or dirty pruning tools?
Using dull pruning tools crushes plant tissue instead of making clean cuts. This creates jagged wounds that are slow to heal and provide entry points for diseases and pests. Dull tools also require more force to operate, increasing the risk of injury to both the plant and the gardener.
Dirty tools can spread diseases between plants. Pathogens like fungi, bacteria, and viruses can easily transfer from an infected plant to a healthy one via contaminated blades. Always sharpen your pruning tools regularly and disinfect them with a solution of diluted bleach or rubbing alcohol before and after each use.
How close to the main stem is too close when pruning a branch?
Cutting a branch flush with the main stem or trunk removes the branch collar. The branch collar contains specialized cells that are essential for the plant to compartmentalize the wound and heal properly. Removing it prevents the plant from forming a protective callus, leaving the area vulnerable to decay and infection.
Instead of flush cuts, prune branches just outside the branch collar, leaving a small stub (about 1/4 to 1/2 inch). This allows the plant to naturally seal the wound without damaging the surrounding tissue. The stub will eventually dry and fall off, leaving a smooth, protected scar.
Why is it important to identify the plant before pruning?
Each plant species has specific pruning requirements based on its growth habit, bloom cycle, and overall health. Attempting to prune a plant without knowing its identity can lead to improper techniques, resulting in reduced flowering, stunted growth, or even plant death. Different plants also react differently to pruning, with some tolerating heavy pruning while others are easily stressed.
Knowing the plant’s name allows you to research its specific pruning needs and learn about its natural growth patterns. This information will guide you in making informed decisions about when, where, and how much to prune, ensuring the plant thrives and maintains its natural beauty.
What is the problem with pruning at the wrong angle?
Cutting a branch at an incorrect angle can impede proper healing and increase the risk of disease. If the angle is too steep, it can create a large, exposed wound that takes longer to callus over. Conversely, an angle that is too shallow can leave an excessively long stub, which is prone to decay.
The ideal pruning angle is typically around 45 degrees to the branch collar. This angle allows for efficient healing while minimizing the size of the wound. It also promotes proper water runoff, preventing moisture from accumulating and encouraging fungal growth.
What is heading and why should it be avoided?
Heading involves cutting a branch back to a stub without regard to the location of lateral buds or branches. This technique stimulates rapid growth near the cut, resulting in a dense cluster of weak, upright shoots often referred to as “witches’ brooms.” These shoots are structurally weak and susceptible to breakage.
Heading also disrupts the plant’s natural growth habit, creating an unnatural and often unsightly appearance. It can also lead to reduced flowering and fruiting as the plant prioritizes vegetative growth over reproductive growth. Thinning cuts, which remove entire branches back to their point of origin, are generally preferred for maintaining plant health and aesthetics.