Rejuvenation pruning is the aggressive cutting of stalks, or stems, of certain shrubs to the ground in late winter. There is a limited group of plants that consistently respond well to this type of pruning. I only have experience with the ones I have worked on in eastern Massachusetts.

Forsythia is a great example. On March 26, 2022, I did a partial rejuvenation pruning of a large, old and tired forsythia. I cut some large, older stems on the back side of this plant to the ground. This was in a very visible location, and the client was concerned about losing screen and how the plant would look in the short term. So instead of cutting the entire plant to the ground, we did a partial pruning.

If you are going to take the partial approach, start by cutting down the larger, older stems. You can cut down portions of the older wood over the course of a few years. By taking this strategic approach, you can preserve most of the plant. However if you want to be aggressive with the right species in late winter, you can cut the entire plant to stubs 3 inches above the ground. Believe it or not, it will grow back younger and healthier.

Set expectations

It’s important to set your client’s expectations. Even though I have done this for a long time, every time I cut plants completely to the ground, I offer this disclaimer. “If the operation is a success, you can visit the patient. If not, you can claim the body.” That’s my corny way of saying, “If a couple of plants die, don’t be surprised.”

This rarely occurs, but it can happen. There have been a few instances of cutting down entire privet hedgerows when a plant or two was lost.

Inform your client that it will take a few years for the plant to grow back to the previous size. If that is going to be a problem, take the partial approach over a few years. Usually, these types of plants grow back over the course of a few seasons. As the term “rejuvenation pruning” suggests, you replace your old, tired shrubs with younger, vibrant shrubs. And it’s a lot less expensive than replanting.

Important considerations

If you decide to experiment with this type of pruning, you need to know three important things.

• What shrubs will respond well to this aggressive pruning.
• The condition of the plant.
• Prune in March or April.

If you do this to the wrong type of plant, you will either disfigure or kill it. If you try this on a plant that is weak or almost dead, guess what? If you do this in the fall, summer or early winter, even to the right species, you can do more harm than good.

Lastly, for the best results, fertilize the plant in late fall before you prune. In the Northeast, this will be October 15 to December 1, depending on the weather that year. I prefer a balanced, liquid tree fertilizer with 5-10% nitrogen. If the soil temperature is above 45 degrees, the plants will still be actively absorbing nutrients. With the fertilizer actively working in the plants before the pruning, it adds an additional boost that really makes a difference.

Conclusion

Rejuvenation or basal pruning is a great tool to have in the pruning toolbox. Just remember the decision pruning-guide matrix before you prune anything.

• Species: Know your plants and how they will respond (always the hardest one).
• Timing: What time of year?
• Condition: If I prune this plant, am I doing more harm than good?
• Expectations: How long will it take for the plant to respond? Will my client be upset if it looks bad, they lose screening and it takes a long time to grow back?
• Follow up: Will there be more work I need to commit to doing in the future, because every plant will have a reaction to pruning?

David M. Anderson, Certified Treecare Safety Professional (CTSP) and a Massachusetts certified arborist, is a manager with Mayer Tree Service Inc., a 30-year TCIA member company based in Essex, Massachusetts.