Many tank mixes are designed to provide a synergistic effect. In other words, you can use lower rates of both products to get the same or greater efficacy. Although we have found no synergism with tank mixes of Configure (6-BA, Fine Americas, Inc.) and growth retardants, we saw good response when Configure was tank mixed with the growth retardant Piccolo (paclobutrazol, Fine Americas, Inc.).
So, to give you some examples, we compared an untreated control with foliar applications of 600 ppm Configure, 120 ppm Piccolo, or a tank mix of 600 ppm Configure plus 120 ppm Piccolo using three crops, Echinacea ‘Doubledecker,’ Heuchera ‘Silver Lode,’ and Leucanthemum ‘Becky.’ The sprays were applied about 10 days after potting. Plants were evaluated for height and number of branches over the production period. Only the Echinacea flowered during the trial.
Echinacea. Plant height of Echinacea ‘Doubledecker’ was reduced by all PGR applications at 2 weeks after treatment (WAT) but only those PGR applications including 120 ppm Piccolo resulted in shorter plants at 4 WAT (Photo 1). Thereafter, the persistent 40% reduction in the vegetative plant height of Piccolo-treated plants was not statistically significant, which suggests variability in our plant growth. Plant width was only mildly affected, significantly reduced by all treatments at 2 WAT but only by the Piccolo only treatment at 4 WAT.
Only the PGR applications including Configure increased the number of basal branches of Echinacea. This increase of over 100% in the number of branches persisted through the 12 week study but did not translate into a significant increase in the number of flowers per plant. Numbers of flowers per pot at 12 WAT: Control 6.7 vs. Configure 9.9 vs. Piccolo 5.3 vs. Configure + Piccolo 6.4. Flowering was delayed (less than one week) with this rate of Piccolo but flower height was not reduced by either Piccolo application.
Heuchera. Neither plant height nor width of Heuchera ‘Silver Lode’ was affected by Configure or Piccolo relative to the control plants. Because of the compactness of the crown, it is very difficult to get an accurate count of branches on Heuchera. So, we conducted a destructive harvest to get the 4 and 6 WAT basal branch counts. We found that the number of basal branches was increased by either Configure or the Configure + Piccolo application (Photo 2). So the density of the plant was increased, again improving pot fill.
Leucanthemum. Plant height of Leucanthemum ‘Becky’ was reduced by all treatments at 2 WAT but the differences were not significant at or beyond 4 WAT (Photo 3). Plant width was reduced moderately, but significantly, by Configure + Piccolo treatment at 4 WAT, and by both treatments containing Piccolo at 6 WAT. Both treatments containing Configure increased the number of basal breaks of Leucanthemum at 2 WAT. These results persisted for the Configure treatment at 4 WAT. These plants did not flower for us.
Tank mixes of Configure and Piccolo work well to improve plant branching as well as to maintain control of plant growth on responsive crops. Our results do not support any suggestion of synergism in the effects of these combined products.
We found similar results with tank mixes of Configure plus Concise (uniconazole) or with Configure plus Dazide (daminozide). Therefore, select your Configure rate and your growth retardant rate based on the needs of the crop and your own experience.