Controlling Stem Elongation in Perennials
One study evaluated the use of ethephon substrate drenches to regulate stem elongation in containerized herbaceous perennials. Results demonstrated that targeted applications can successfully control plant height without compromising overall plant health, allowing growers to produce uniform, high-quality plants suitable for retail markets.
Growth Management in Annual Bedding Plants
A complementary study quantified the effects of ethephon substrate drenches on a range of annual bedding plants. Researchers found that controlled applications can effectively limit excessive growth, resulting in more compact plants with improved aesthetic appeal. These insights provide valuable guidance for growers seeking cost-effective and efficient growth management strategies in greenhouse and nursery production.
Industry Implications
Effective height and growth control are essential for both aesthetic quality and operational efficiency in ornamental horticulture. The research provides actionable information to help growers enhance plant uniformity, reduce labor-intensive pruning, and improve overall crop marketability, supporting more sustainable and profitable production practices.
This research was led by W. Tyler Rich, current research associate, as part of his Master of Science degree in the Department of Horticulture and Crop Science at The Ohio State University. The work was conducted to support label expansion of Collate® 2L (ethephon). As of May 2025, Collate ® 2L is the only ethephon product with EPA approval for substrate drench use as well as foliar sprays. These findings support grower adoption, application timing, and responsible use in floriculture production.
W. Garrett Owen is an extension Specialist and Assistant Professor of Sustainable Greenhouse Nursery Systems. His major program initiatives include floriculture crop production, plant nutrition and growth regulation, nutritional monitoring, and crop diagnostics.
The full story can be found on the ASHS HortScience electronic journal website at: https://doi.org/10.21273/HORTSCI18418-24 and https://doi.org/10.21273/HORTSCI18579-25
Established in 1903, the American Society for Horticultural Science is recognized around the world as one of the most respected and influential professional societies for horticultural scientists. ASHS is committed to promoting and encouraging national and international interest in scientific research and education in all branches of horticulture.
Comprised of thousands of members worldwide, ASHS represents a broad cross-section of the horticultural community - scientists, educators, students, landscape and turf managers, government, extension agents and industry professionals. ASHS members focus on practices and problems in horticulture: breeding, propagation, production and management, harvesting, handling and storage, processing, marketing and use of horticultural plants and products. To learn more, visit ashs.org.
