Growth Regulator on hedges?

[rxqx]

I have a few accounts that have some rather large bushes/hedges that are very time consuming to trim. Has anyone used a growth regulator so you would not have to trim as often? if so, what is it called and where could I buy it?

Any suggestions on your experiences or application tip would be greatly appreciated. Thanks,Ryan

[lorenzo piedra]

One needs to be a licensed certified applicator in the category of ornamental trees and a carry a commercial insurance policy with a pollution endorsement to apply chemicals for hire.

[Seascape]

No wonder your such a dick stone.

[lorenzo piedra]

Michael Seascrape front and center!!!


Instead of making off color mowronic juvenile comments towards your superior why can't you just answer the gentleman's question?

[highlander316]

You could always up the price of charging the hedges so you make more.

[Stephen M.]

If you are licensed, use Atrimec. It works great and costs around $300 per gallon. That's not alot of money if it saves you money.

One of my clients has a laurel hedge that usually requires 4-6 trimmings per season to keep it looking nice, This year it was cut twice and after each cutting, it was sprayed with Atrimec. The 1st cutting/spray was end of May and the 2nd cutting and spray was mid August. The hedge still looks perfect.

I only use Atrimec on my contractural clients. I'm not anxious to sell it to people who call me 1-2 times per year to do pruning/hedging.

[Jacksson]

If it requires more of your time, then doesnt that also mean it requires more of your customers money? Wheres the problem?

[Seascape]

Michael Seascrape front and center!!!


Instead of making off color mowronic juvenile comments towards your superior why can't you just answer the gentleman's question?

I have bolded your answer in this literature rxqx. Please excuse my drunken babble.


October 2003
Have You Considered Tree Growth Regulators?
By Rex Bastian
As commercial arborists, we are expected to deal with trees growing in many different types of situations. Improving our knowledge about how trees function and the treatment options available to us is very important. If we can identify the positive and negative impacts affecting the trees on a given site, we can select the appropriate management options. The more management options available to us, the better chance we have of finding the best solution for our clients.

Growth regulators have been used in horticultural industries for many years. They are commonly used in the greenhouse industry to produce compact bedding plants for landscape use. Poinsettias are treated to keep them from getting leggy. Turf managers use them to increase mowing cycles and improve color and stress resistance. Growth regulators have potential uses for arborists, too. Benefits include growth reduction, improved root development, improved resistance to water stress, and improved color. Potential disease resistance effects are also under study.

Paclobutrazol is a chemical that has several applications for commercial arborists. While it should not be considered a "silver bullet," we should be aware that it exists, and that it is another potential tool in our tree care management arsenal. Paclobutrazol is available to commercial arborists under two trade names, Profile® 2SC (Dow Chemical, Inc.) and Cambistat® 2SC (Rainbow Treecare Scientific Advancements).

Paclobutrazol affects woody plants in several different ways. Most attention has focused on its ability to regulate shoot growth. Originally screened as a fungicide, its growth regulatory effects were noticed in the early 1950's. Plants treated with paclobutrazol show a reduction in shoot growth compared with untreated trees. The chemical causes this effect by interfering with the natural production of gibberellins by the treated plant. Gibberellins are responsible for cell elongation in plants. Paclobutrazol does not inhibit the production of new cells, only the elongation of the cells once they have formed.

Utility arborists were among the first to recognize the potential benefits of growth regulators. Pruning cycles could be extended and the amount of chips generated reduced by treating with growth regulators. Some of the methods used, such as trunk implants and trunk injections, did cause trunk injury and/or sporadic results.

The formulations of paclobutrazol available to arborists are not injected into the trunk. They are placed in the soil around the trunk flare of the tree. They can be injected, using an injection device such as a Kioritz injector or fertilizer probe. They can also be applied as a soil drench. The growth retardant effect of paclobutrazol has many applications. How many times have you seen trees that have outgrown the space available to them, either above or below ground, or both? How many times have you seen trees that are still within their bounds, but likely to exceed them in the future? Examples include trees next to sidewalks, shrubs under windows, and trees in planter boxes. I know, wrong plant in the wrong place. Still, slowing the growth down with a growth regulator may salvage a few more years, right? Once again, we are talking about an option. Perhaps it is not the perfect solution, but it may be an appropriate solution for certain clients under certain conditions. Slowing down the growth of a tree may be preferable to removing the tree and starting over. That would be for the client to decide.

Work by Gary Watson at the Morton Arboretum shows that trees treated with paclobutrazol have higher fine root densities compared with trees not treated. This has applications for trees recovering from root-related damage such as following transplanting or construction. It would also have application for trees where root space is limited. A possible reason for the increase in fine roots is that more carbohydrates are available to the roots because of the reduced top growth.

The secondary effects of paclobutrazol (improved drought stress, darker color, disease resistance) occur as a result of the chemical's primary affect upon gibberellin production. Gibberellins are produced as the end product of a series of complex chemical reactions within the plant. Think of these reactions as an assembly line. If any one portion of the line breaks down, the number of assemblies prior to the breakdown point begins to build up. Two choices are now available: 1) fix the line or, 2) find another use for the intermediate assemblies. In plants, because paclobutrazol prevents the gibberellin assembly line from being fixed, the plant uses the intermediate chemicals for other uses.

Let's take a look at how the plant uses these intermediate chemicals and see how we can use them to our advantage. One of the intermediate chemicals can be used to make abscisic acid. Abscisic acid regulates the opening and closing of stomates in the leaf. Stomates are important in regulating gas and water exchange between the leaf interior and exterior. Increased levels of abscisic acid result in greater stomatal closure. This reduces water losses from the leaf, potentially improving resistance to drought. Work by William Chaney at Purdue University shows that the leaves of treated plants maintain higher moisture levels for a longer time.

Therefore, treating trees in droughty situations may reduce wilting and subsequent leaf scorch due to excess water loss from the foliage. Remember, such a treatment cannot be expected to prevent scorch. Treatment may provide a cushion of a few extra days to provide the trees with water or to allow for rainfall.

Intermediates in the gibberellin pathway can be used by plants to synthesize chlorophyll. Higher chlorophyll levels can result in darker green foliage, improving appearance. Even though shoot growth is reduced, photosynthesis is not reduced. One must remember, however, that if other factors are limiting the production of chlorophyll (nutrient availability, compaction, water-logged soil, etc.), little benefit can be expected.

Intermediates also appear to be used by plants to produce compounds that inhibit steroid production in fungi. Fungi require steroids to form cell membranes as they grow. Plants treated with paclobutrazol may have reduced levels of fungal disease when compared with nontreated plants. Research is continuing to investigate and document these observations. Be aware that paclobutrazol formulations are not labeled as fungicides, and cannot be used specifically for that purpose. To do so would violate the provisions of the Federal Fungicide, Insecticide, and Rodenticide Act (FIFRA).

While there are many opportunities to use growth regulators to our advantage, risks do exist. To manage and minimize risk, we must identify those situations that can get us into trouble. Growth regulators are powerful chemicals. A single paclobutrazol treat- ment can affect trees for three to six years. Careful records must be kept to reduce the risk of over-application.

Tree species vary widely in their response to paclobutrazol. Lindens and maples are very responsive, while ash and most conifers require much higher rates. As with any chemical, proper dosing is crucial. Because of the long term effect of a single treatment, an improper dose can affect a tree's appearance for many years. Species dosing guides have gotten much better with work continuing to add more species. Stick to tree species listed on the label or in the guides. Overregulation causes a "pompom" or "poodle" effect on the foliage. While not necessarily harmful to the tree, it can upset clients because they are not expecting such a change. It is important to let your clients know that there may be a change in the appearance of treated trees. Many prescription drugs have side affects. Chemicals that affect plants are no different.

Remember that growth regulators will affect plants beside trees. Flowers, shrubs, and turf near the treated areas will be affected as well. Think before you act and plan accordingly.

Many factors affect how an individual tree will respond. Time of application, soil type, organic matter content, tree size, etc. can all play a role. Most soil or trunk applied materials are subject to the same factors. Growth regulators are no different.

Finally, growth regulators are not the answer for every tree growing in a tree pit or that has been subjected to construction injury. They should not be considered a fix for poor design or management decisions. If you cover a red oak's root system with a foot of compacted clay, a paclobutrazol treatment isn't going to save the day.

Growth regulators are options. They give us more alternatives than we had before. Learn what they can and cannot do. Try them on a few sites. Watch and see how treated trees respond. Ask other arborists if and how they are using these products. And remember, the learning never stops.