Tree Growth Regulators

Growth regulators have many benefits in the landscape:


RTSA-Treated-Leaves-Cambistat (1)Twenty-five years ago, growth regulators were mostly 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 benefiting trees in ways beyond growth regulation alone, including:

  • Drought Tolerance
  • Greener Leaves
  • Disease Resistance
  • Root Growth

When growth regulators are applied to the root zone of a tree or shrub value can be added by:

  • Extending the time between trimmings, which helps maintain a tree’s size for at least 3 years.
  • Creating healthier trees by increasing root hair growth.
  • Increasing drought tolerance.
  • Redistributing carbohydrates (trees make their own food through photosynthesis) from growth to storage and fine roots.
  • Extending the lifespan of trees by reducing stress from limited root space.
  • Extending the serviceable life of a tree planted too close to a building or utility wires.
  • Correcting mild micronutrient deficiencies.
  • Allows the tree to grow steadily, requiring less pruning and providing added tolerance to certain diseases and insects.


See Also: Growth Retardants: A Promising Tool for Managing Urban Trees

How does is all work?

All trees and shrubs contain a Growth Hormone called Gibberellic Acid or GA for short. GA is principally responsible for cell expansion and to a lesser extent cell division (the process of branch growth). The active ingredient of the growth regulator reduces the effects of GA on the cells. The direct effect is a dramatic reduction in vegetative growth, especially internodal elongation. Which means, the size of treated trees can be effectively regulated by up to 90% for at least 3 years, depending on use conditions. Since many fungi are also affected, treated trees show significantly less effects from a range of plant diseases.

Tree growth regulators are applied by calculating the amount of solution required for the specific tree. The specific amount depends on the type and size of the tree. The mixed solution is then poured as a drench around the base of the tree. The active ingredient is then taken up by the roots and distributed to the tree’s growing points, where vegetative growth reduction can be seen.

The amount of time for root uptake and distributed to the growing points varies according to soil type, soil conditions, time of year and tree species. The growth control is approximately 40-60%, varying by species. Effective growth control generally lasts for about 3 years and then needs to be re-applied.

Contact Arbor Doctor now to learn how growth regulators can benefit your landscape. You can use our simple online booking calendar to schedule your landscape evaluation now.

Please note that some visits have a cost associated with them. Follow up service for current customers is ALWAYS free. Landscape evaluation charges are credited 100% if we perform a service for you.

February Moisture Condition Monitoring Report

Condition Monitoring Report
Station Number: OH-HM-24
Station Name: Cheviot 3.4 W
Report Date: 2/17/2017
Submitted: 2/17/2017 7:20 PM
Scale Bar: Near Normal
Observed conditions are expected for this time of year. February rainfall is below normal with only 0.96 to date and only 0.18 in the last 7 days. Temperatures have been above normal but cool enough to keep soil moisture evaporation to a minimum. Conditions were wet in January and conditions have only recently returned to near normal for this time of year.
Categories: General Awareness

What’s wrong with the blue spruce trees in my neighborhood?

Colorado blue spruce trees have long been among the most popular conifers for landscaping in Michigan and the upper Midwest. Blue spruce trees are widely planted due to their good growth rate, stately form and, of course, their blue foliage. Unfortunately, blue spruce trees are subject to a wide range of insect and disease problems that can impact their growth and aesthetic appeal.

The prevalence of diseases on blue spruce trees has intensified in recent years and trees are declining rapidly in many areas… Read the entire article here>>> 

Biochar: A Game-Changer for Soils

By Dave Story in The Landscape Contractor

Everything old is new again. That certainly holds true for biochar, a type of charcoal first produced and used in the Amazon basin centuries ago to make agricultural land more fertile. Biochar results from heating plant waste, or biomass, at high temperatures in little or no oxygen. The process, called pyrolysis, also takes place in naturally occurring fires resulting from lightning strikes. Not only does biochar help soils retain nutrients and moisture, but it remains effective in the soil for hundreds of years – all of which means it can help you better and more efficiently protect the health of your clients’ landscapes. Read more here>>>

January 21, 2017 Moisture Condition Monitoring Report

Condition Monitoring Report
Station Number: OH-HM-24
Station Name: Cheviot 3.4 W
Report Date: 1/21/2017
Submitted: 1/21/2017 7:53 AM
Scale Bar: Severely Wet
Soil is wet. Ground is completely saturated with water. Standing water is abundant. Water bodies are very elevated. No flooding. 11 consecutive days with measurable rainfall with no drying. 2.75 inches rain in past 11 days. Any field work or excavation is difficult to impossible right now due to wet conditions.
Categories: General Awareness
Business And Industry

Fireblight This Time


From the BYGL…

Fireblight on Callery pear is highlighted against the blue sky in Columbus’s German Village this past Thursday in the lead photo of this byglalert, with a different look in the second photo taken with a different sun angle, important to remember when seeing images and thinking “it doesn’t look quite like what I saw”. Fireblight symptoms of “shepherd’s crook” shoots and discolored leaves are common to see now, following infections which occurred weeks, even months earlier in cool, warm weather during bloom.

Disease Digest

Published on

June 12, 2016


Jim Chatfield

Overwintered Bagworm Eggs Have Hatched and Caterpillars Are Feeding

1st Instar Bagworms on Arborvitae

Overwintered common bagworm (Thyridopteryx ephemeraeformis) eggs have hatched in southwest Ohio and 1st instar caterpillars have settled to feed and construct their characteristic sac-like bags.  A percentage of the tiny 1st instar caterpillars produce a strand of silk upon hatching to catch the wind and “balloon” to new locations.  This behavior is one of the reasons bagworms often appear on hosts that were not infested last season.

Published on
Joe Boggs

Sycamore Anthracnose


 BYGL Update…

Enquiring eyes throughout Ohio are noticing sparse foliation on sycamores (American planetree) and to a lesser extent London planetree hybrids this Spring. Not to worry, the culprit is almost assuredly sycamore anthracnose disease.  This fungal disease occurs every year, but is enhanced when there are cool, wet conditions during leaf emergence, conditions which were common throughout Ohio this year. If history is to be any guide, these planetrees will recover well, putting out new leaves which will make us forget how they look now by late June.


The fungus overwinters in…

Published on
Jim Chatfield
Joe Boggs

Black Knot is destroying Canada cherry trees

Black Knot Not Black

boggs.47 Wed, 05/04/2016 – 08:13

Black Knot of Prunus is caused by the fungus, Apiosporina morbosa, and is characterized by thick, corky, elongated gall-growths on twigs and branches.  The common name of the disease is based on the coal-black coloration of older galls late in the growing season. Currently, newly sporulating black knot galls are olive-green or reddish brown and may have a velvety texture.  Newly forming galls may appear as simple swollen growths causing the bark to crack; they may be mistaken for a cankering disease.
While cankers can be pruned from purple plums, in Canada cherry it is so aggressive and virulent that attemps to prune it out or treat it are futile. Arbor Doctor recommendation: do not plant Canada cherry.
Published on
Joe Boggs

Updates From The BYGL–Boxwood Dieback and Aliens of Cedars

Junipers Garnished with Tangerine Tentacles and Orange Goo.

Our wet weather this spring has triggered spectacular spore production by three types of rust fungi on junipers in southwest Ohio.  All three fungi belong to the genus Gymnosporangium and each must alternate between a member of the plant genus Juniperus and members of the rose family (Rosaceae) in order to complete their life cycle.  The requirement to cycle between two types of widely divergent host plants coupled with the rusty color of their spores earns these fungi the collective moniker of “heteroecious” rusts.

Published on
Joe Boggs

Widespread Decline Being Noted In Local Spruce Populations

We have been noting significant needle drop in local spruce trees, particularly blue spruces.

Spruce Needle Casts (Rhizosphaera and Stigmina)

Spring has barely sprung and the Plant Clinic has already received a number of samples this year. Most common have been spruce and pine samples with a variety of issues including the ever-present fungal needle casts (Rhizosphaera and Stigmina on spruce, Diplodia and Lophodermium on pine). Read more here>>>


This Twenty-Something Hopes to Unleash the Next Green Revolution

By Andrew Jenner on August 29, 2014 in Modern Farmer

In 2010, a young man on a quest for enlightenment walked into the office of Jerry Hatfield, director of the USDA’s National Laboratory for Agriculture and the Environment in Ames, Iowa. His name was John Kempf, and he was eager to learn more about Hatfield’s plant physiology work, which deals with the complicated interactions of plants, soils and the atmosphere.

The two talked agronomy for several hours before Hatfield sent Kempf on his way with a stack of literature to devour. The visit was just one of many steps on Kempf’s journey, which had begun six years earlier in a blighted cantaloupe patch. Desperate to rescue his family farm from worsening disease and pest problems, Kempf dove into deep-end science, looking for solutions he couldn’t find in the conventional farming playbook.

In the process, Kempf became a staple on the alternative-ag lecture circuit and the CEO of a rapidly growing consulting firm that his followers hail as the next best thing in sustainable, profitable agriculture. The most hopeful even say that he and his company offer a glimpse of a better farming future, uniting the best that our various schools of agricultural thought have to offer.

Kempf is just 26 years old. He is also Amish, and has only an eighth grade education.  Read more >>>>>