Tree pruning is the removal of certain parts of the tree to improve its overall health, shape, and growth pattern. Done right, it's healthy for developing plants. Improper pruning, however, can prove disastrous, and may prevent a tree from flowering, make it susceptible to disease, or even kill it. This article will go over some basic, safe techniques on how to prune in a way that’s best for the tree.
Best Time to Prune
The short answer is, it depends on when the tree blooms! Pruning at the right time ensures that cuts will heal, disease spread will be minimal, and flower or fruit development will be enhanced.
In general, the best time is early spring, since most trees are summer bloomers, and pruning aids in new growth. If you have an early spring bloomer, however, you should wait until after they flower. Same with fall or winter blooms.
Large, deciduous trees may benefit from pruning in the winter when the tree is dormant, and you can easily get at the leafless branches. Fall is generally the worst time for most trees, as they prepare to go dormant, and pruning would incur too much stress.
If you need to remove hazardous limbs or sections that are diseased, you can do this any time of the year, since these are emergencies in their own right—just stick to cutting away the specific area.
Remember, there are some tree-specific diseases that run rampant through wounds caused by pruning. Check individual species of trees, and if they are susceptible to pruning diseases before you do any work. There will be safe times to prune when disease transmission will be dormant. Pruning on dry days is best, as rain and moisture can help to spread microbial disease.
The majority of pruning is what’s called "cleaning," which is essentially general maintenance. This includes the removal of dead, diseased, and weak branches from any part of the tree, or pruning for basic shape. Remember to remove any suckers, which shoot out directly from the base of the tree, as well as water sprouts which point directly upward in a straight line from the dominant branches at the top of the tree.
Extensive cleaning only needs to be done if there are obvious issues like the ones mentioned above. While annual maintenance is recommended, you can leave a tree to its own devices if it looks healthy and symmetrical, and it's producing growth.
"Thinning" involves removing specific branches to allow more light inside the canopy, improve air flow, and generally correct the shape of the tree where branches have filled in too densely. Mainly used for hardwood trees, it’s also deployed to take out any heavy branches causing stress to the overall plant.
Too much thinning can be destructive, so make sure not to remove more than 25% of a tree at one time. It’s also better to focus on the outer limbs when possible, or any branches that are criss crossing.
"Reduction” pruning is used when a tree is obstructing a residence, building, or other kinds of infrastructure like telephone lines. This technique cuts back long branches to reveal secondary limbs. These inner branches must be at least one-third the size of the branch you're cutting so they're strong enough to assume the new role as what's called a "terminal branch," to which the tree sends nutrients.
Smaller branches can be removed back to the main branch to which they're connected. Try to do any reducing as evenly as possible.
To allow more clearance for cars or pedestrian walkways, “raising” involves pruning the lower branches from a tree. Mature trees can withstand losing up to a third of their lower branches, however very young trees need their lower branches while they're growing, so this kind of pruning should be limited in less mature plants.
Raising is best done regularly and over a longer period of time, with smaller cuts to allow the tree to heal, so it lifts its canopy naturally.
Proper Pruning Cuts
Pruning cuts are important to keep trees as healthy as possible, but they always stress a tree to some extent. Proper technique will help minimize any trauma.
Always prune back to just above a growing point like another branch, a bud, or the trunk—never leaving a long stub sticking out. When possible, use a 45 degree angle—this keeps the wound small and allows water to run off easily.
The top of any cut should ideally be above any buds or healthy growth, and angling away. High quality pruning sheers are recommended. Keep them sharp so the cuts are clean.
Young trees will benefit from proper pruning methods as they start to mature. By focusing on healthy development along the way, you will ensure the tree won’t require any drastic pruning in later years to correct major issues.
Essentially you want to focus on establishing the tree’s framework by promoting strong, primary branches. Healthy, young trees have one main leading branch that extends upward. This dominant leading branch should never be pruned, whereas any secondary branches should be so that they don’t outgrow it, helping the tree form a nice, even shape.
Get in the hang of adding pruning to your yearly garden to-do list to keep issues from getting out of hand. In most cases, a little maintenance every year will keep trees strong and healthy, allowing them to produce beautiful flowers, leaves, or fruit.