Effects of paclobutrazol and chlormequat on growth and flowering of lavender

Abstract

Growth retardants allowed production of more uniform, compact, flowering plants for commercial use of lavender (Lavandula stoechas). Paclobutrazol at 200, 400 and 600 mg.L-1 (ppm) was sprayed in a single or double application. Chlormequat was applied at 4000, 6000 and 8000 mg.L-1 in single, double or triple spray applications repeated every 13 days. Paclobutrazol reduced lateral shoot elongation and plant height, increased the number of nodes within lateral shoots, but delayed time to anthesis. In contrast, chlormequat reduced plant height with no effect on flowering. Paclobutrazol potentially may be used commercially on lavender at rates of 200 to 400 mg.L-1 in single or double applications. The same result may be achieved with chlormequat by using 4000 to 6000 mg.L-1 in three or more applications.