Plant growth regulators (PGRs) can be sustainable and cost-effective options that benefit both the lawn care operator (LCO) and customers when applied correctly.

PGRs help operators cut down on labor hours, equipment use and the amount of product needed, says Derek deBloois, owner/operator of DeBloois Landscaping in Milford, Del.

DeBloois uses Nufarm’s Anuew, with the active ingredient prohexadione calcium, and T-Nex, with trinexapac-ethyl.

“On our maintenance accounts, we have reduced double-cutting, extra edging and line-trimming times by 50 percent. We view this product as a tool and time-saver,” deBloois says. “This also can have a color effect on turf without the application of more NPK.”

His company offers lawn care, soil testing and corrections, overseeding, aeration and also a small amount of mowing and landscaping. The company serves 95 percent residential and 5 percent commercial customers.

DeBloois says his crews use a zero-turn spreader-sprayer to apply a liquid formulation of Anuew.

“We feel our dual-pump setup on this machine gives us the flexibility of running 1 to 2 gallons per thousand square feet,” he says.

Following the label

DeBloois recommends LCOs closely follow the product’s label and wear proper personal protective equipment (PPE). He adds that PGRs are best applied during the spring — early April to mid-May —and it’s also best to water the product in and apply it as evenly as possible.

“We tend to avoid the product in the summer as heat and humidity can naturally stunt growth on non-irrigation properties,” deBloois says. “The correct wind and weather conditions are key with this product.”

Achieve uniform coverage

Mizraim Mata, plant and turf healthcare manager at The Greenery in Bluffton, S.C. says that PGRs promote a denser, more lush appearance to the landscape. He adds that they also reduce the amount of maintenance needed because of the slowed growth.

The Greenery offers lawn care, aquatic management, garden center, landscape construction and maintenance services to 80 percent commercial and 20 percent residential properties.

While application timing varies by location, LCOs should typically apply PGRs during the growing season, ideally in late spring or early summer, Mata says. Backpack or handheld sprayers are common for applications in smaller areas, whereas larger properties might require ride-on or truck-mounted sprayers.

Mata says that The Greenery uses Trimtect from Rainbow Ecoscience, which features a commonly used active ingredient — paclobutrazol — which inhibits the production of a plant hormone that is responsible for cell elongation.

Specific PGR and application rates will vary depending on factors like the plant species, environmental conditions and desired outcome, according to Mata.

“Applying these substances results in reduced vertical growth of plants, promoting lateral growth and a more compact appearance,” he says. “This can lead to benefits such as decreased pruning frequency, enhanced plant quality and improved stress tolerance.”

Mistakes to avoid

Applying PGRs during the wrong time of the growing season can diminish the effectiveness, Mata says.

He adds that using excessive amounts of PGRs can also have negative effects, such as stunted growth or discoloration. Mata recommends that LCOs follow the manufacturer’s recommendations for application rates.

Mata also says that operators should avoid application during extreme weather conditions like droughts or high temperatures since that can negatively impact the efficacy of PGRs and potentially harm the plants.

Inaccurate calibration of the equipment can also lead to uneven, ineffective results. LCOs should regularly assess the health of the plant to check for signs of stress or disease and adjust the PGR application or address other issues.

“By incorporating these practices into their PGR application routine, lawn care operators can optimize the effectiveness of the treatment and promote healthier, more attractive landscapes for their clients,” Mata says.