Illinois State Florists' Association
REGULATION OF the growth of garden annuals by the application of growth retardants was reported by Ca they (1). B-Nine (N-dimethylamino-succinamie acid ) was the growth relardant used. Experiments reported in this paper were conducted mainly on petunia plants. The optimum dosage varied greatly. A 0.5% foliar spray of B-Nine applied when the main stem started to elongate regulated stem height, reducing it by one-third (Table 1). Plants were compact and flowering was not de layed (Fig. 1). Blue Magic, Pink Velvet. Snowbird, and Calypso responded only slightly to a 0.5% B-Nine treat ment. Three weekly sprays of 1.0% B-.Nine also had little effect. However, when Ballerina, Comanche Improved, and Red Satin were treated with the same concentrations, flowering was delayed and size was reduced. A 0.25% treatment of the latter, more-sensitive varieties, produced plants two-thirds the height of the untreated petunias. Environment Influences Efficiency Temperature and daylength also regulated the growth rate of petunia plants (1), and the environment greatly influenced the efficiency of B-Nine treatments. When plants were grown on long days and night temperatures* of 65°F or above, and given one foliar application when the stem started to elongate, height was reduced by one-third. During natural days in March and April when temperatures were below 65°, it was difficult to control height with one foliar application of B-Nine.
Source: • Illinois State Florists' Association Bulletin #258
Keywords: Treatment Temperature and daylength Foliar application Responses flower size