In a significant breakthrough for ornamental horticulture, recent studies have revealed that ethephon substrate drenches can effectively regulate stem elongation in containerized herbaceous perennials and annual bedding plants. Conducted at The Ohio State University, this research highlights how targeted applications can maintain plant height without compromising health, allowing growers to produce uniform, high-quality plants ideal for retail markets.
The announcement comes as growers increasingly seek sustainable and efficient methods to manage plant growth. By ensuring compact and aesthetically appealing plants, these findings offer a cost-effective solution for greenhouse and nursery production.
Controlling Stem Elongation in Perennials
A study led by W. Tyler Rich, a research associate at The Ohio State University, evaluated the use of ethephon substrate drenches on containerized herbaceous perennials. The results demonstrated that these drenches could successfully control plant height, ensuring uniformity and quality without affecting overall plant health. This development is crucial for growers aiming to meet the high standards of retail markets.
Growth Management in Annual Bedding Plants
In a complementary study, researchers quantified the effects of ethephon substrate drenches on various annual bedding plants. The controlled applications were shown to limit excessive growth effectively, resulting in more compact plants with enhanced aesthetic appeal. These insights are invaluable for growers looking to implement cost-effective growth management strategies in their operations.
Industry Implications
Effective height and growth control are vital for both aesthetic quality and operational efficiency in the ornamental horticulture industry. The research provides actionable information that can help growers enhance plant uniformity, reduce labor-intensive pruning, and improve overall crop marketability. This supports more sustainable and profitable production practices, aligning with industry trends towards eco-friendly and efficient horticultural methods.
The move represents a significant step forward in the adoption of ethephon drenches, particularly with the EPA-approved Collate® 2L product, which is currently the only ethephon product approved for both substrate drench use and foliar sprays. As of May 2025, these findings are expected to guide growers in application timing and responsible use in floriculture production.
Expert Insights and Future Directions
W. Garrett Owen, an Extension Specialist and Assistant Professor of Sustainable Greenhouse Nursery Systems, emphasized the importance of these findings. His major program initiatives include floriculture crop production, plant nutrition and growth regulation, nutritional monitoring, and crop diagnostics, all of which stand to benefit from the research outcomes.
“The ability to control plant growth without compromising health is a game-changer for the industry,” said Owen. “These studies provide a blueprint for sustainable and profitable horticultural practices.”
The research was published in the ASHS HortScience electronic journal, further cementing its credibility and relevance. Established in 1903, the American Society for Horticultural Science (ASHS) is a leading authority in horticultural science, promoting research and education worldwide. With thousands of members globally, ASHS represents a diverse cross-section of the horticultural community, focusing on a wide range of practices and challenges in the field.
For more detailed findings, the full studies can be accessed at the ASHS HortScience journal website through the following links: Study 1 and Study 2.
As the industry continues to evolve, these studies provide a foundation for future innovations in plant growth management, paving the way for more sustainable and efficient horticultural practices worldwide.
