Tree care

What Are Growth Regulators?

Growth regulators are the newest ugly duckling story to hit the plant health care scene. Twenty-five years ago, growth regulators were a niche within a niche. They were utilized by large utility companies to keep trees out of power lines, but largely ignored by tree health professionals. Today, growth regulators are better understood, widely used, and benefitting trees in ways beyond growth regulation alone. How can growth regulators improve the overall plant health, you ask?


Save Time and Money

The use of growth regulators can save you time and money by reducing your trimming frequency. The time from spring to early summer is busy. Very, very busy. The lawn is growing and needs mowing. The weeds are coming up. The bedding plants and other colorful flowers need to get in the ground. Taking shrubs out of the peak season equation can dramatically free up labor to accomplish these other tasks. 


Improved Plant Appearance

Growth regulators allow the plant to allocate energy that would be used for vegetative growth to be directed to other functions. This available energy is utilized in other areas such as defense compounds and fine root development, resulting in a number of plant benefits. You will see darker green plants, a more compact look, and enhanced plant appearance & quality.


Disease Reduction

While not specifically designed for disease maintenance, there are many instances where the application of a growth regulator has had a positive impact on the severity of symptom expression of certain diseases.


Improved Root System

Research has shown that plants treated with growth regulators show an increased production of fibrous roots. This helps the plants by expanding the area of soil from which the plants can pull water, minerals, and other resources.


Growth Control

This seems like it goes without saying, but there are many situations in the urban environment where slowing or reducing the vegetative growth of plants can be beneficial to the plants and to the properties they grow on. Plants near infrastructure, large and unruly plants, or plants that are particularly leggy are a few examples. 

Customer Satisfaction

When it comes to maintenance, we often want our shrubs to look perfect. Plants that have been treated with growth regulators stay looking their best for longer, keeping you happier for longer as well!


Drought Tolerance

Plants treated with growth regulators undergo several changes that help them be more resistant to drought conditions, including:

  • Increased abscisic acid production allows stomates to close faster when dry.
  • Increased trichomes (leaf hairs) protect leaves from drying wind.
  • A thicker cuticle (waxy) layer prevents desiccation.
  • Increased fibrous root system allows plants to better mine water from the soil.
  • Reduced growth requires fewer resources to maintain.



Safety is a primary concern for everyone involved in landscape maintenance. This includes the safety of the tree service crews working onsite, as well as anyone who accesses the site such as motorists or pedestrians. There are several ways that the use of growth regulators improves safety on the job site, including: 

  • Reduced use of dangerous equipment such as chainsaws, chippers, power shears, or loading equipment.
  • Less time spent climbing up ladders to trim.
  • Reduction of sidewalk lifting



Interested in how growth regulators can benefit you? Contact a trained arborist to get a professional opinion on what steps to take next.