Chemical care: Cutting back

It doesn’t take an efficiency expert to know the less time you spend on each jobsite, the more opportunity you have to expand your clientele and, thus, your profits. There are many ways to boost how effectively you implement time-saving measures, but one that is growing in appeal is use of plant growth regulators on ornamental plants. These products have proven to decrease labor by as much as 50 percent, according to John Spaulding, PGR product manager, PBI/Gordon. Want to know if they are right for you? Spaulding fields some common questions about PGRs.

Can this category of PGRs be used on all ornamentals?
Different products (such as PBI/Gordon’s Embark and Atrimmec, and SePRO’s Cutless) are labeled for use on different ornamentals, depending on how the manufacturer has tested them. “Our labels tell users that, because it is impossible for us to test all species, they should do their own testing prior to using a PGR on a species not listed on the label,” says Spaulding. “Our labels list only plants for which we have developed test data and we specify the rate for each labeled species.”

Are PGRs more effective on some ornamentals than others?
Yes, which is why rates will vary by plant species. “Depending on the growth habit of the plant, the type of PGR used and the rate used, effectiveness will vary,” says Spaulding. “That is why we have developed specific rates for specific plant species.”

How do they work?
“Embark works by slowing cell division. Atrimmec works differently; it stops apical growth and promotes lateral growth,” says Spaulding. “Dikegulac sodium, the active ingredient in Atrimmec, is broadly used to manage the growth of ornamental plants. Atrimmec causes the terminal meristematic regions of a plant to stop growing, while lateral growth in the meristematic regions is stimulated. This results in fuller, more compact plants with increased florescence. This unique characteristic has been put to use by many innovative landscape professionals to save storm- or insect-damaged ornamentals, avoiding costly replacement,” he says. Atrimmec has a very broad label and is effective on a number of different plants.

How often (on average) is the application?
“The frequency of the application will depend on plant species and the length of the growing season,” says Spaulding. “In most areas, a single application will last most of the growing season.” Embark and Atrimmec are liquid spray products, while Cutless (SePRO) offers a granular form.

Do they compromise the beauty of the plant (or its ability to produce flowers, if applicable)?
“Occasionally an applicator will get a slight temporary discoloration after a PGR application,” says Spaulding. “But this is temporary. Atrimmec can act as a chemical ‘pinching’ agent, actually causing flowering plants to produce more flowers. It is sometimes used in floriculture for this purpose.

“Conversely, properly timed application of Atrimmec can prevent fruit set in ornamental fruit trees to prevent the messy drop of ripe fruit later in the season. This year we added a new application method to the Atrimmec label for this type of application. Applicators no longer have to apply a foliar spray to trees to prevent olives; they can just spray the bark or drench the roots, making this a much more appealing application.”

In what pricing situation could landscape professionals most benefit from PGRs?
“We have landscape professionals who tell us that they could not service all their accounts without Atrimmec. In any bid situation that involves the maintenance of ornamentals, an ornamental PGR is going to give them an edge,” says Spaulding. “PGR use for ornamental growth control has become standard for many businesses. If they are a grounds crew, they will save labor, labor, labor.”

If you’d like exact numbers regarding what you could save by using a PGR, PBI/Gordon features an online cost/savings calculator. Go to

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