- To maintain plant vigor.
- Create and preserve a good branch or plant structure
- Increase flower or fruit production on fruit trees.
- Improve overall health and air flow.
- Keeping the plant size to the space in which it is planted.
People often find themselves pruning shrubs or trees more often because they have been planted in a location where mature size was not taken into account. The excess growth can lead to encroaching on other plants, screen windows, or spill into the lawn spaces and walkways.
A common mistake is pruning a plant purely by its appearance rather than looking at its natural growth factors: size, width, shape, growth rate, and determining the best course of action from there. If possible, it’s important to start pruning plants when they’re young as it is easier to maintain a well pruned tree. It’s important to cut back conservatively and knowledgeably, otherwise the plant often ends up worse off than if you just left it alone.
The first step to starting with good pruning practice is to select a high-quality plant from a reputable garden center who has been pruning it correctly from the early stages. This will create good branch structure and a good balance that will eventually establish well. Starting with healthy plants that have “good bones” makes a huge difference.
Some Things to Consider Before You Prune
It is a known fact that more pruning in young, vibrant shrubs and trees increases the amount of new growth. This means that if you prune too often, it can make the situation worse or even require more attention than if you had just left it alone. With older trees that have lost a lot of their vigor, a good heavy renovation prune often stimulates new growth of the tree and helps produce more branches, flowers, or fruit. Just like mowing grass weekly, when pruning a shrub or tree it is recommended that no more than 1/3 of the height be taken off per year to avoid stress on the tree or shrub.
Timing your pruning also has a lot to do with the species that you are working on. There is a spring and early summer prune which will help take off a lot of the new flushed growth and prohibits a lot of new shoots. You should be careful on fall pruning of some items as this can stimulate new flushes of growth that can be damaged by early frosts and cold freezes.
For flowering type shrubs and trees, it’s important to determine if the species will flower on the new buds from the current season or the previous season’s growth. Knowing this will help you decide when it’s best to prune and reduce cutting off the new potential flowers. We have found that if you prune in the dormant season, and take off growth with buds that would have developed in the spring, it will help the plant flower more and develop a stronger branch structure. This also helps reduce the time that the open wound is susceptible to disease before active growth starts.
There is definitely a benefit to pruning shrubs and trees for the right reasons. It’s always good to take off any dead, diseased, or dying material at any point. This will reduce the stress on the plant, reduce the wounded area from insect and disease damage, and allow the wound to heal correctly. If you put thought and consideration into what you are trying to accomplish and what outcomes you hope to have, this will drive how you do your pruning, when you do it (depending on species), and will also help you decide if you really have the right plant for the area.
Proper Pruning Tools
- Loppers: used for larger branches up to 1” in diameter.
- Pole Pruner: used for different size branches that are further up in the canopy of the tree that cannot be reached from the ground or ladder. These have a lopper-type cutting ability as well as a heavily toothed saw that is used for larger branches.
- Hedge Shears: used to shape smaller shrubs with very fine or thin branches.
- By-Pass Pruners: this type of pruner has the blades slide by side like a pair of common scissors.
- Anvil Pruners: this is a sharp blade that pushes down on a flat, small metal surface on the pruner to cut the branch.
- Chainsaw: used for larger branches that cannot be cut by a pole saw or other method.
It is very important that you sanitize your tools before you start pruning anything. A simple 10% bleach and 90% water solution is the easiest way. It is recommended that you do this between each type of plant and cut that is being made to reduce the chance of spreading a disease. Although it is not common to spread disease through pruning, there is some risk, and sanitizing your tools will reduce that risk greatly. It’s also a good idea to always start with your known healthy plants and then finish pruning any plants or shrubs in question.
When you start to prune your plants, you need to consider what the mature look of the plant is and make your pruning cuts accordingly. The type of cut and where it is made will have a big impact on how the wound heals, along with how the new branch structure will grow out and effect the health of the plant in the future. It is said that most species of shrubs and trees will respond to the cut similarly as long as it is done the right way.
Different Types of Pruning Cuts
There are several different types of cuts that can be made during the pruning process depending on what the condition of the plant is, what you are trying to accomplish, and the species of the plant as well:
- Heading Cuts: this is when the new growing part of the branch is taken off, which then stimulates the lower buds to push out a vigorous flush of new growth. This method is often used when you want to create a dense type of growth like shaping a small shrub, hedge, or tree. If you are using this method only to keep the plant size down, you have the wrong plant for that location.
- Pinching: this method is used by taking off only the new growth on the stem or branch, which then pushes out new growth from the buds below that to develop into branches. The more often this is done, the denser the branch structure will become as the plant grows. For example, we see this type of practice a lot in the growing of annual plants or fall mums that have 3-4 pinches in a 6 month period to shape and build out the density and fullness of the plant.
- Thinning Cuts: these types of cuts are taking off more than the small new growth at the tip. It is cutting back down to the first or another lateral branch which then will put energy back into the growth of that lateral branch rather than pushing out new growth at the pruned location. This method is often used to help open up air flow inside the canopy of a tree, cut crossing branches out, and decrease the height.
- Removal Cuts: this is one of the heavier cuts made which results in taking the branch right back to the main stem or trunk of a large tree. It can be utilized when trying to limb a tree up from the ground.
Branch Collar and Branch Bark Ridge
When making cuts during pruning, it is very important that each cut is done with the correct angle as trees and shrubs do not have the ability to heal “tissue”. Instead, they create a barrier of cells to reduce the damage of the wound. The cut angle is easy to establish once you are able to identify the key features on the branch. These features are the “branch collar” and “branch bark ridge”.
- Branch Collar is the swollen area that is found right where the branch and trunk tissue connect at the start of growth.
- Branch Bark Ridge is the area of the branch in which there is raised bark that the branch and stem meet at. This area is crucial to the health of a tree because the “woundwood” is located inside this area, which has cells that help form tissue to protect the tree from decay after cuts are made.
When you start to prune, the cut needs to be right above the branch collar and at the same angle as the branch bark ridge. If you cut below or your cuts are flat, this reduces the amount of woundwood and the trees ability to fully heal the wound, which then opens the tree up for decay and insects.
If you are worried about doing this process, you can always start out on a small shrub or tree in an inconspicuous location, take a photo of the area you are about to prune, and make the proper cut. Then, in a few months, return to that same shrub or tree and see how your pruned area has developed based upon your pruning technique. Start small until you are comfortable and confident in what you are doing. There are many books, online articles, and resources to refer to in making the right decisions on timing and techniques. And, as always, our experienced staff at Stephens Landscaping Professionals is here if you want your pruning expertly taken care of.