A Pruning Guide

by David Anderson

David will lead a hands-on pruning demonstration and discussion on March 9th at the ELA Conference.

As landscapers and horticulturalists pruning is a very important part of our work. Most horticulturists are passionate about pruning. Most people enjoy pruning and believe in their methods. There are as many different styles of pruning as there are people, but how do you know what’s right?

Pruning should be more than just removing branches. You need a plan before you begin. Over several years, Hartney Greymont, offering tree service in the Boston area, has developed the pruning decision process. Before we prune we ask a few important questions that lead us to a specific plan.

Intent

  • What am I trying to accomplish with this particular plant? The answer can be as simple as removing dead wood or as complicated as creating an espalier.
  • Do you want the plant to look attractive when the pruning is complete or will it take time to respond to the pruning? What are my aesthetic expectations?
  • Your intent is the easiest question, but you need an answer before you begin.

Species

  • Will this particular plant respond well to my objective? This is the most difficult question. It requires strong knowledge of the plants you work with and experience of how each species reacts to pruning.

Timing

  • What is the best time of the year? Our general rule is if you are going to prune something aggressively the best time of year is late winter/early spring. The idea is that you are capturing all the energy the plant is generating to push new growth. This energy is channeled to react to the wounding. Pruning in late winter or early spring leaves the plant with a more natural shape from late spring through the end of the year.
  • The classic example of aggressive pruning is rejuvenation or basal pruning. Cutting down stocks of shrubs to get new sprouts from the base of the plant. The timing of this approach is species specific, but it can “rejuvenate” old plants.
  • January and February are a great time of year to prune most deciduous plants especially large trees, but not a good time to prune most evergreens.
  • If your intent is to have the least reaction or sprouting, the best time of year to prune is late summer and fall. If you prefer plants to have a manicured appearance then schedule pruning at this time. The plants will retain this neater look until late spring next year.
  • People always ask about losing flower buds. This should be a lower priority because you want to manage the plant with a longer view than one season.

Dose

  • How much can I remove at once? How often will I need to prune the plant to accomplish my objective? Once I have the desired result what is the pruning schedule going forward? These decisions require a basic understanding of the particular plant.
  • Our general rule: the more formal the intent the more work, both in the short term and in the future. Formal hedges, espalier, topiaries, and Bonsai require the greatest commitment. This prompts another question: Do I have the time and resources to commit to my intent? Do not start something that will require multiple prunings if you cannot stay the course.
  • Over pruning is worse than not pruning at all. Timing and species are critical to dose. A general rule is to not remove more than 25% of the foliage. Most of the time that is a good rule, but there are instances when less or more is appropriate. You need to have a specific plan for each plant.

Condition

  • Is this plant healthy? There are several things that can weaken the plant: insects, disease, drought stress, old age, etc. If the plant is not healthy, then pruning beyond dead wood may do more harm than good.

So many factors to be considered; however, using the pruning decision process provides a guide. These rules are pragmatic but not set in stone. Pruning is a mix of science and art. The most important thing to consider is that you are wounding the plant. How will this plant react? As you know, plants can be forgiving and a big part of learning is trial and error. Like most things, people have their bias about their pruning style. This is wonderful and we should always be open to learning and debate. However there are a few important things that should not be compromised.

Making the proper pruning cuts separates the professionals from the amateurs. As mentioned before pruning is wounding the plants. It is imperative that these wounds are made in the best possible manner. Plants do not heal; they continually grow and that is how they close the wound. Leaving stubs or cutting into the stem you are pruning back to should be avoided. Plants are forgiving, but making the proper pruning cut promotes healthier plants.

Invest in Tools

Since the accuracy is so important to a proper cut it is important to use good, sharp pruning tools. They can be expensive but are worth the investment.

Safety is the most important thing. Work on plants that you can prune safely. Ladders, pruning tools, weather, terrain, bees’ nests and many other factors make pruning potentially dangerous. Make sure to use the proper personal protective equipment. Gloves, safety glasses, hardhat and hearing protection when appropriate must be used. Think in terms of what can go wrong. Have a plan that allows for the safest way to do the work. This is your most important priority.

There is so much more that can be discussed and written about pruning. This is a simple guide to help you start the process, but the best way to learn is by doing. Pruning is a very important maintenance practice and it can be rewarding. When you set a goal using the pruning decision process, and it comes to fruition you know you have created something special. It gives you a sense of pride seeing a beautiful healthy plant because of your work. Isn’t that ultimately why we work with plants?

About the Author

David M. Anderson is a Massachusetts Certified Arborist and a Massachusetts Landscape Professional with over 20 years of experience in tree and landscape care. He was the Chairman of the Massachusetts Certified Arborists Board for three years. He has authored articles for trade publications and gives presentations to various groups on a wide variety of horticulture subjects. David works for Hartney Greymont as an Arborist Representative consulting on projects in and around Boston.

David will lead a hands-on pruning demonstration and discussion at the ELA Conference on March 9th.