COMPARISON OF APPLICATION METHODS OF PACLOBUTRAZOL FOR HEIGHT SUPPRESSION OF POTTED TULIPS
in HortScience`Kees Nelis' tulips were potted five bulbs per 0.8-1 container using a commercial peat moss and perlite growing medium. Bulbs were exposed to 9C for 4 weeks, followed by 5C until the emerging shoots were 4 to 5 cm long. One day after plants were moved from the cooler to a greenhouse (14C minimum), the following treatments were applied: drench or spike (International Spike, Inc.) of 0.062, 0.25, or 1.00 mg paclobutrazol per pot; or drench of 0.25 mg ancymidol per pot. Flowering height was reduced linearly as concentration of paclobutrazol increased for both application methods; flowering height was 24.0 cm with the highest rate of paclobutrazol, 23.8 cm with ancymidol, and 27.7 cm with untreated plants. Treatments had no effect on flower diameter or time to flowering.
