Why plant growth regulators are the industry’s best-kept secret

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Plant growth regulator, or PGR, is a catch-all term for many different products that slow the growth of shrubs, turf and trees. Korey Lofy, Rocky Mountain territory manager for Arborjet, says often landscape professionals keep their PGR program close to the chest.

“Many landscape companies don’t like to tell their competition they are using PGRs because of the massive advantage of labor savings and plant appearance,” he says.

While some in the green industry might be hesitant to talk about PGRs, Drew Calvert, landscape division manager with Ribeiro Landscape in Las Vegas; Lee Hickman, owner of Charleston Grounds Management in North Charleston, S.C.; Shawn Fitzgerald, regional manager for Phoenix Landscape in Ocean Isle Beach, N.C.; and Kathy Glassey, director of plant health care with Monster Tree Service, share how plant growth regulators give their operations a boost.

Better use of labor

Fitzgerald says plant growth regulators help keep his workers safe in areas where there might be more risk to workers pruning. Phoenix Landscape offers commercial lawn care, maintenance, enhancements and right-of-way clearing.

In one homeowner association Phoenix Landscape services, Fitzgerald says hedgerows extend for at least two miles on a berm, and the plant material is high, which means crews use ladders to prune the plant material. Instead of pruning the hedges four or five times, crews apply the shrub growth regulator Trimtect and only prune once or twice a year.

“Right off the bat, you’re reducing labor down by 33 percent, if not better than that. And it adds up to thousands of dollars in labor cost savings.”

Hickman also says using PGRs helps him cover more ground with his commercial maintenance crews. He says he’ll often send crews out in February to deploy the first round of PGR applications with Trimtect on shrubs. Crews will make a second application as summer transitions to fall.

“This year, when everybody else was pruning, our guys were not pruning. We were more focused on getting our mowing and other tasks done,” he says.

He estimates his crews used to prune Ligustrum six to eight times a year before he started using plant growth regulators.

“We’re pruning that shrub, maybe one time a year as a full prune,” he says. “We’re probably tip pruning two times a year. We’re going from six prunings down to no more than about three.”

Large canopies

Calvert deploys Atrimmec for canopy management on commercial properties. He says he favors using PGRs on “labor suckers” such as oleander hedges. “They could put as much as 6 to 8 inches of growth,” he says. “In tandem with Atrimmec, you can reduce at least one pruning cycle.”

Crews apply Atrimmec through bark banding, which Calvert says prevents drift and selectively applies the PGR to the intended plant.

“The tree actually absorbs chemical through the cambium and saves us a lot of time,” he says.

Keys to success

Fitzgerald says companies that add PGRs should ensure all technicians understand how to apply them. Landscape professionals often blame the product instead of the applicator when issues arise.

“Make sure that you train the people to do it the right way, so you don’t have any mishaps,” he says.

Monster Tree Service applies Shortstop 2SC as a soil drench and as a foliar spray for shrubs. Glassey says it’s important to apply the product after pruning, and it’s critical to follow the product label for recommended rates for each plant species. Time of day is important, too.

“We always prefer to treat trees and shrubs before the heat of the day sets in and never apply when temperatures exceed any label recommendations,” she says.

Hickman advises being patient. Crews may still need to do more pruning in the first year of applications.

“You really see the ROI that second year,” he says. “In that second year, that shrub already has the growth regulator in its system. You’re not getting those shoots going crazy; you’re just getting a very few selective shapes to where the guys can actually go around just hand snip.”

For pricing, especially on shrubs, Lofy suggests landscape professionals take several factors into account.

“The landscape professional needs to consider the product cost, labor savings and competitive advantage of using PGRs,” he says.