Controlling Growth of Ornamental Millet
Plant growth regulators (PGRs) are valuable tools utilized by greenhouse growers. Whether it is for promoting or controlling growth, PGRs give growers the opportunity to produce high quality crops in the face of their production or shipping challenges. Over the past year, the sustainable floriculture and nursery research lab (Owen Lab) at The Ohio State University has received multiple inquiries about controlling growth of ornamental millet (Pennisetum glaucum) during summer and fall production. As such, we performed PGR substrate drench research trials where we investigated multiple PGR active ingredients (chemicals), concentrations, and ornamental millet cultivars. We have found that substrate drenches containing 8 to 16 ppm ancymidol, 4 to 8 ppm flurprimidol, 4 to 8 ppm paclobutrazol, or 1 ppm uniconazole controlled plant height of ornamental millet without negatively affecting visual appearance of the plant. Flurprimidol at 16 ppm and uniconazole at rates above 2 ppm negatively affected the visual appearance where plants were extremely stunted, and leaves were crinkled. For the rates we found to successfully control growth, we suggest that growers use these as starting points and trial in-house before applying to a whole crop. Growers should adjust the rates as needed based on environmental and cultural conditions during ornamental millet production.
W. Garrett Owen
Assistant Professor of Sustainable Greenhouse and Nursery Systems, The Ohio State UniversityW. Garrett Owen is an Assistant Professor of Sustainable Greenhouse and Nursery Systems in the Department of Horticulture and Crop Science at The Ohio State University. He has an appointment in research, teaching and Extension. His area of expertise is plant nutrition; plant growth regulation; and production problem diagnostics.
