Organizing Theory & Artistry

Landscaping Basics: Pruning

Pruning fruit tree. Placer County, California (1940). Photo by Russell Lee for the Farm Security Administration. From the Library of Congress Prints and Photographs Division.

I have a lot to do to tune-up my front entrance plantings. We have let them become rather jungle-like over the years in part due to lack of time but also because of lack of knowledge. Most of our front entrance plantings are various bushes and shrubs. What are you supposed to do to make bushes and shrubs look good? Apparently a key requirement is good pruning.

Pruning is an old-fashioned sounding word that basically means trimming the plant either for aesthetic reasons or to improve the health of the plant. Most of us have probably never learned how to prune correctly. When I told my husband about this post, his first reaction was, “I probably have been too aggressive with the hedge trimmer, eh?”

I don’t doubt that most people assume that pruning requires power tools. Yesterday I was a little surprised to see two men from the park service with chainsaws cutting off relatively small branches from trees and bushes as they walked along a path in a local park!

Pruning done right is more of a delicate process and not a mass hacking off of branches.

“In most cases, it is better not to prune than to do it incorrectly.”

–Douglas F. Welsh and Everett Janne, “Follow Proper Pruning Techniques,” Texas Agricultural Extension Service, the Texas A&M University System

How do trees and shrubs grow?

Now is a great time to look around your garden to see where your trees and bushes are growing. The new growth occurs at the ends of branches and is generally much lighter in color than the old growth. You can see some examples below:

Spring growth on a holly branch.

Spring growth on an azalea bush.

At first, I thought that this must be the ideal time to prune–when you can see where the new growth is coming in. Apparently this is not so.

“Do not prune at the convenience of the pruner, but rather when it results in the least damage to the plant. . . . In general, the best time to prune most plants is during late winter or early spring before growth begins. . . The least desirable time is immediately after new growth develops in the spring. A great amount of food stored in roots and stems is used in developing new growth. This food should be replaced by new foliage before it is removed; if not, considerable dwarfing of the plant may occur.”

–Douglas F. Welsh and Everett Janne, “Follow Proper Pruning Techniques,” Texas Agricultural Extension Service, the Texas A&M University System

What are the best tools for pruning?

There are a variety of tools that can be used for pruning. Pruning shears and lopping shears are probably the most common and easy for anyone to use with little effort. I really like the Fiskars shears we have. I initially chose them because Fiskars makes really nice scissors for sewing and I have not been disappointed. They cut very well. If you are skilled with power tools and you are doing a lot of pruning, electric hedge trimmers or a chainsaw may be useful.

Fiskars pruning shears at amazon.com.

Fiskars lopping shears at amazon.com.

It is very important that your pruning tools be kept clean and sharp. In a way, you are performing surgery on the plant and just like surgery on people you want the cuts to be quick and sharp and not spread disease to the “patient” in the process. If you are cutting a diseased plant it is recommended that you clean your pruning tools with bleach or alcohol after every cut!

Where do you cut?

While most plants are fairly resilient and will withstand rough treatment, a bad pruning cut could make the tree or shrub susceptible to disease or structurally weakened. The correct place to make a pruning cut is to follow the branch down to the “branch collar,” i.e. its connection to the trunk or main stem, and then cut the branch off at the branch collar. The branch collar is like a natural band-aid for the tree or shrub and has special properties that helps protect the plant from disease and seals off the cuts.

Where is the branch collar? Generally it is kind of hard to see but it is about 1/4” or so away from the intersection of the branch to be cut with the main stem or trunk. Fortunately, the holly tree in my front yard provides an easily-viewable color-coded example. The branch collar is the brown trunk-like protrusion where the new green growth starts. To prune, you just cut at a slight angle at the branch collar.

Close-up of the branch collar on a holly tree. (The swollen portion where the green growth begins.)

Pruning at the branch collar.

On most branches, the branch collar is not so easy to view. Below is an example pruning of my azalea bush. You can see from the photo that I missed the branch collar by just a bit and should have cut a little closer. Sometimes, however, your cutting angle makes it hard to get a precise cut, so you just have to do the best you can.

Point of intersection of dead branch with main stem on an azalea bush.

Azalea pruning. I could have been a bit closer to the leaf collar.

Be careful cutting the top-most branches.

If your idea of pruning is just taking the hedge trimmers and cutting along the top of the tree or bush, you might end up “topping” the tree. Topping means cutting off the main leader stem. This somehow sends a message to the rest of the plant that it needs to stop growing upward. You will still see growth on the tree but it is generally not as healthy as what you would see if you left the leader in place.

My Conservative Pruning Results

Armed with all this information, I headed out to my yard. It was still a bit confusing to know where to start. Cutting the “suckers” (i.e. the very small branches trying to grow on established tree trunks) was easy and a no-brainer. I cleaned up the holly tree and the dogwood.

Trunk of holly tree before pruning. Covered with "sucker" branches.

Trunk of holly tree after pruning. Clear, clean lower branches.

Next, I noticed a dead branch hanging from the dogwood tree. It was not too high off the ground and was relatively small so I felt comfortable cutting it down myself. (Note, for larger, heavier branches, be very careful! You might need a professional.) Using my ladder and lopping shears, it was quickly gone.

Dead branch hanging from the dogwood tree.

Dogwood tree canopy after removing dead branch and a few suckers.

Next it was time to tackle the various hedges. Almost every hedge had new growth on it. While it would have been easy to just cut the new growth, I am going to wait a bit per the advice above and will prune again in a few months once the new growth is more mature. One thing that was fairly easy to do, however, was to cut out dead branches. The dead branches are a bit hard to find at first glance but once you study the bush, you can pick them out and cut them off. It is a subtle difference but it does help the yard look better maintained. I did this on the azalea, boxwood and the rhododendron. Every once in a while, I made an “oops” cut and took out a branch with good growth on it but not very often. Sometimes the dead branches have small leaf-like growth on them. You can still cut these off.

Overgrown boxwood before pruning to remove dead branches.

Boxwood after removal of dead branches.

Rhododendron before pruning. It's chaotic shape is due to snow damage. I kind of like it.

Rhododendron after pruning to remove dead branches. Subtle improvement.

As I went along, I found a lot of small dead branches that appeared to be leftover from my husband’s hedge trimming. I just picked these up by hand. My front yard still has a ways to go but it does look a bit more organized now. I have a garbage can full of dead branches to show for my efforts.

Do you prune? What is your pruning tool of choice? Have a pruning horror story? Please share in the comments. Have a great weekend!