Abstract

A study conducted in 1998 and 1999 determined the effects of B-Nine (daminozide) at rates of 2500 to 7500 ppm, Pistill (ethephon) at rates of 125 to 1000 ppm, Bonzi (paclobutrazol) at rates of 33 to 99 ppm, and Cutless (flurprimidol) at rates of 50 to 150 ppm on vegetative growth and flowering of Canna x generalis ‘Florence Vaughan’ during nursery container production and landscape establishment. Vegetative height 30 and 60 days after treatment (DAT), vegetative and inflorescence heights at first flower, and vegetative height at 30 days after planting (DAP) in the landscape were reduced by Cutless in 1998 and 1999. Vegetative height was suppressed quadratically by increasing rates of Cutless, an average of 46% and 42% (1998) and 19.5% and 30% (1999) at 30 and 60 DAT, respectively. In 1998, Cutless delayed flowering one to six days, while in 1999 flowering was accelerated one to eleven days compared to untreated plants. At 30 DAP, height suppression from the lowest rate of Cutless was 5% in 1998 and 14% in 1999; however the effect was not significant at 60 DAP. With increasing rates of Bonzi, vegetative heights at 30 DAT and at first flower were suppressed 16% to 29% and 12% to 25% in 1998, respectively, but not at all in 1999. In 1998, inflorescence height at first flower decreased linearly to a maximum of 20% as Bonzi rate increased, with no effect in 1999. B-Nine did not affect vegetative or inflorescence height or flowering in 1998 or 1999, except for a three-to eight-day delay in flowering in 1998 and an one-to six-day acceleration in flowering in 1999. The only observed treatment effect of Pistill was a 9% to 17% linear height reduction at 30 DAT in 1999. B-Nine and Pistill did not exhibit effective, consistent height suppression in the 1998 or 1999 experiment and do not appear useful in controlling canna lily height.