The researchers tested different amounts of a plant hormone called gibberellic acid on African marigold plants at two growth stages. They found that using a high concentration of gibberellic acid at a later growth stage led to taller plants, more branches, longer flowering time, heavier flowers, and higher flower yields. On the other hand, using the same high concentration of gibberellic acid at an earlier growth stage resulted in faster flower bud initiation and earlier flowering. The control group had the lowest values for all these measurements.