Using a Growth Regulator for Attractive, Healthy and Manageable Trees

growth regulator

When you planted the tree – as a sapling – all those years ago, the yard was still mostly a blank canvas. In fact, when the tree was initially placed in the ground, it needed to be staked, and it somehow it made the yard look even more barren. Over the years, though, it grew so slowly that it was almost imperceptible unless you compared it to the pictures you took for Instagram on that first day (#nofilter).

During that same period of time, the rest of your property had also undergone substantial changes – changes that will become increasingly problematic as the tree continues to reach maturity.

It was hard to imagine the tree ever towering at the 40 or 50 feet listed on the tag.

But here it is.

Or maybe the tree had been planted by a former resident, now long gone, so you’ll never be able to ask them what they were thinking when they decided to put this particular kind of tree in this particular location.

The problem may have been a long-time coming, but it’s here now.

Today, the tree is too close to the house, the street or the sidewalk.

Today, its canopy is too close to the power lines (which might not even have been there when the tree was planted).

To buy yourself time, you’ve been pruning it back every year, but the cost of all those pruning visits is starting to add up.

This tree is a cherished part of your property, so removal isn’t an option.

There has to be a better way.

Our Plant Health Care division has an alternative solution to yearly prunings that can actually make your tree healthier. You’re working hard to maintain the size and health of your tree, but there is a way to achieve the desired results by working smarter, not harder.

Applying a Growth Regulator

As authorities in plant health care, our crews are most often called out to:

  • Protect trees from invasive/destructive insects
  • Diagnose and treat plant diseases
  • Apply fertilizers to help trees grow strong
  • Identify and fix problems at the root level

However, one of the most fascinating services they offer is also one of their least well-known.

They can apply a growth regulator (specifically, a chemical called Cambistat) to the tree to suppress its growth. According to the Cambistat fact sheet, a single application can help reduce growth by 40-70% over a three-year period.

Growth regulators offer several advantages over traditional pruning such as enhancing the tree’s appearance and boosting its health.


Pruning a tree is a lot like getting a haircut: it’s almost always an improvement, but it can take some time to get used to it. As an alternative, growth regulators can improve the aesthetic qualities of the tree, and many of our customers prefer the more “natural” look that comes with suppressing the tree’s growth at just the right time.

The tree will experience less height growth while the suppressant is in effect, but the leaves will continue to develop normally. In fact, they will often be thicker and greener because of the treatment.


While suppressing a tree’s growth might sound like it could be potentially harmful to the tree, that’s not the case. Growth regulators can make trees healthier by minimizing stress and making them more resistant to droughts. It is even being looked at as a potential method of helping trees shore themselves up against diseases without cures such as bacterial leaf scorch. In these cases, the Cambistat “in theory allows the tree to invest this energy into defense chemicals and increased root production, which makes the tree healthier” [from “Tree Diseases.” 2017. Tim Abbey, educator with Penn State Mont Alto Extension specializing in Horticulture and Green Industry)].

Accordingly, we often recommend growth regulators for tree-lined streets and parks where the trees are planted and contained in “tree pits.” The growth regulator keeps the trees at a manageable size while preserving their health. It also minimizes the potential damage and safety hazards that can arise from overgrown trees in high-traffic areas.

Is a Growth Regulator Right for Your Tree?

Growth regulators keep trees attractive and – most importantly – manageable. They can, however, disfigure the leaves of some species of trees and Cambistat works better on some types of trees than others. If you are concerned about a tree that is quickly outgrowing its place on the property, contact us today for a consultation.