Get the Most Out of Your PGR

Incorporating a plant growth regulator (PGR) in your operation helps ensure strong, attractive crops by the time they reach customers. PGRs differ by active ingredients, application rates, methods and more, so understanding how to select and use one effectively in your operation is critical for achieving the desired effects.

For example, before selecting the PGR for your operation, be sure to establish your PGR goal because different active ingredients provide different results.

To limit shoot growth and maintain compact plants, use PGRs with active ingredients such as paclobutrazol, ancymidol, daminozide, flurprimidol and uniconazole. These active ingredients target and inhibit gibberellin production, which is responsible for stem elongation. Active ingredients that are plant hormones, including gibberellins and benzyladenine, affect plant development such as plant flowering or branching.

Choose A Proven Solution

Bonzi® ornamental growth regulator ensures plants stay compact and beautiful by keeping them at their peak for longer. It is powered by the active ingredient paclobutrazol, which reduces stem elongation. Bonzi makes transportation less stressful as it strengthens stems for less breakage and plants have an extended, enhanced shelf life. Additionally, Bonzi applications in the weeks prior to shipping provide:

  • Deeper green foliage
  • Brighter flowers
  • Better water-use efficiency
  • Greater heat tolerance
Growth control with Bonzi drench treatments on calibrachoa
Growth control with Bonzi drench treatments on calibrachoa
Lang, Syngenta photo. 2005

Application Timing and Rates

When using a product like Bonzi, it’s important to know the typical development of your crop so you can time the application appropriately. This will help you avoid applying too early, which may shut down plant growth, or too late, which results in leggy plants.

When determining the appropriate application rate, be sure to not only read the product label, but understand how your growing location, the plant species and age will impact the application rate.

Guidelines to remember:

  • Crops grown in moderate-to-warm climates typically require lower application rates than those grown in hot and humid climates.
  • The taller, more vigorous varieties typically require a higher application rate than the naturally short, less vigorous varieties.
  • Younger, smaller plants of the same species will respond differently than older, larger plants even though volume and pot size may remain the same.
  • Remember to only apply Bonzi to plants that are not under stress.
  • The growing medium should be moist for even PGR application for each plant.

After understanding and learning how to use PGRs effectively, they can be valuable tools in your operation to help you produce high quality plants.

Visit to learn more about incorporating Bonzi in your operation, and download the Bonzi Drench Guide.

All photos are either property of Syngenta or are used with permission.

© 2022 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Bonzi®, GreenCast® and the Syngenta logo are trademarks of a Syngenta Group Company.

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