The following are conclusions from research at Michigan State University on using Fascination growth regulator to increase height and bract size in poinsettias.
Fascination can be used by poinsettia growers to increase plant height and promote bract expansion, especially on plants that have reduced bract size from an excessive or late growth retardant application. When warranted, we suggest applying Fascination as a spray at a rate of 3-5 ppm using a volume of 2 quarts per 100 sq.ft. The amount of stem elongation and bract expansion from a Fascination spray depended on the time of application. If an increase in plant height is desired, then Fascination could be used before or soon after first color. During this time, a single spray application at 3- 5 ppm increased plant height by 1-2 inches. A later application (20 or 30 days after bract color) produced little or no increase in plant height. If an increase in bract size is desired, our results indicate that the best time to apply Fascination is 20-30 days after bract color. This late application will also have a smaller effect on increasing plant height. In addition, we noticed that late applications of Fascination made bract surfaces appear smoother and reduced bract crinkling. We did not observe any effect on bract color, although growers have reported that Fascination can slightly lighten the bract color. In some cases, a second Fascination spray may be required to achieve the desired elongation effects. We suggest waiting at least 10 days between spray applications. Frequent applications and high rates can produce an undesirable spacing between the bracts. As with all plant growth regulators, we encourage growers to perform their own trials on a small scale to determine desirable rates for their growing conditions and for each poinsettia variety.
Information from Fascination on Poinsettia by Matthew Blanchard, Mike Olrich and Erik Runkle, Michigan State University