Why Tree Growth Regulators Help Your Tree

Your tree may thrive by being smaller and growing more slowly. That may sound counter-intuitive but developing data seems to support that, in urban and suburban areas, smaller trees enjoy better longevity, richer color and cost you less to maintain.

I was reviewing an article by Tom Prosser, the man behind Cambistat, which is a growth regulator we’ve used in the Denver, CO area over the past five years. We’ve found the results to be predictable and economical.  But why even use a growth regulator?

Control Growth. Removing a tree is a costly undertaking that can leave a barren spot in your yard. Spruce, elm and cottonwoods quickly outgrow their site and a beloved tree may need to be removed. Using a growth regulator once every three years will control the growth. A growth regulator can limit tree growth up to 60%. Different tree species differ in their sensitivity. A dogwood may see its one year shoot growth, inhibited by 80% while a cotton wood as little as 20%. Diameter growth of the trunk, branches and large roots will also be reduced along the same time line as shoots. Leaf growth is not as effected although it can cause leaves to be smaller.

Water Detection A growth regulator can help minimize the production of these larger roots and increase the fibrous root production making you’re tree much more flexible in its all points search for water. Many times your trees roots are dominated by larger, woody roots, but the smaller, fibrous roots are underdeveloped because energy is going to driving shooters and suckers into turf.

Cure Root Damage It can also help with root chlorosis and in any situations were the root system is damaged through soil compaction, drought or construction. Beware that a growth regulator like Cambistat will indirectly increase fruit production on a fruit tree or sweetgum. So if you have a crabapple near a walkway, spraying it with Florel brand growth regulator could help reduce unwanted fruit production on an ornamental tree.

Greener Leaves Research has shown an increase in leaf thickness and the number of trichomes or leaf hairs produced when using a growth regulator. This can help maintain water balance during drought conditions as well. Researchers think the concentration of chlorophyll is increased causing leaves to be a darker green. Fall color and the leaf drop have not shown to be affected.

How Do Growth Regulators Work

Modern growth regulators were developed in the 1980′s as a better solution. The first type killed tree cells on contact and worked like a light herbicide. The second type of growth regulators do not kill tree cells, but limit the elongation of them creating smaller cells and a smaller tree.

Tree size maintenance can help trees steer clear of powerlines, buildings and other structure. It can reduce the overall cost of trimming, use of defense treatments, fertilizer. The tree itself can last longer while using fewer resources. Studies indicate that smaller trees stay health have a greater degree of root growth and endure urban stresses better.

Brands of growth regulators included Profile 2SC, Cambistat, which is a systemic treatment. Florel which is directly applied as a foliar spray will help with the reduction of nuisance fruit on ornamental trees and not much else.