Cyclanilide Promotes Shoot Production and Flowering of Coreopsis and Coneflower during Nursery Production

Herbaceous perennials were screened for increased branching and flowering in response to foliar sprays of cyclanilide (CYC), a plant growth regulator with cytokinin-like activity. Coreopsis verticillata ‘Creme Brulee’ (‘Creme Brulee’ coreopsis) and Rudbeckia fulgida ‘Goldsturm’ (‘Goldsturm’ coneflower), the only two species that responded positively to CYC, were used in subsequent experiments evaluating CYC concentration, method of application, and stage of plant development at application. Foliar sprays of 25 to 100 ppm CYC promoted increased shoot development, flowering, and plant width of coreopsis and coneflower, although flowering was delayed. Applying foliar sprays to both species when they were vegetative resulted in similar or more new shoots and flowers than an application when plants exhibited early signs of approaching flowering or at both stages. Increases in shoot counts from the application of substrate drenches of CYC to coreopsis and coneflower generally were less than from foliar sprays, while flower counts either decreased with increasing CYC concentration (coreopsis) or were unaffected (coneflower). Species used in this study: Coreopsis verticillata L. ‘Creme Brulee’ (‘Creme Brulee’ coreopsis), Lantana ×hybrida hort. ‘New Gold’ (‘New Gold’ lantana), Pennisetum setaceum (Forssk.) Chiov. ‘Rubrum’ (purple fountain grass), Perovskia atriplicifolia Benth. (Russian sage), and Rudbeckia fulgida Aiton ‘Goldsturm’ (‘Goldsturm’ coneflower).