Generally, it will take two weeks to see the effects of the treatment, and the effect lasts three to six months. Over time, you may require fewer treatments because weaker muscles atrophy and require fewer injections.
The hibiscus is a heavy feeder that prefers frequent but light fertilizing. A nitrogen fertilizer in the spring and a high potassium fertilizer in the summer work well for the hibiscus plant. Also, fertilizing at the beginning and during the growing season gives the hibiscus needed nutrients for growth.
The key to success with heavy-feeding hibiscus plants is to fertilize lightly and often. Hibiscus should be fertilized at least once a month throughout the growing season, and the schedule should be kept up regularly. Remember that numerous light applications of hibiscus fertilizer are always better than a few heavy applications. See chart for feeding amounts.