I have a yellow hisbiscus which bloomed for one day and closed up during the same evening, however on the 2nd day the flower had fallen off. I did not find any insects or abnormal pests visually. What could I have done better?
Hello, thank you for contacting the Toronto Master Gardeners with your Hibiscus question. I was not sure from your message if indeed you only had one flower. If so, you are probably wondering why only one? And why did it drop off?
Hibiscus are spectacular when bursting with bloom, but many times we hear from gardeners that their plant, although healthy, is not producing the number of flowers expected. One of the main reasons for this often is the amount of light your plant is getting. In order to flower abundantly your Hibiscus requires at least 6 hours of direct light per day. Your plant can certainly survive with less, but it will not produce many flowers.
Hibiscus also requires good rich soil, moist – but not soggy. You may wish to check the soil medium in which your Hibiscus is planted to make sure that is draining properly. These plants suffer if left in soggy soil, rot can quickly set in and one of the first signs is buds dropping. Lack of fertilizer may also be the reason for the lack of flowers. Is your plant in a container? If so, you will need to feed your plant as the potting soil does not have the nutrients needed for bloom. Look for a balanced fertilizer and make sure you do not over fertilize as this will burn your plant. Kelp meal is a good organic fertilizer to encourage blooming in Hibiscus.
Buds dropping from Hibiscus is often caused by thrips, but if you have checked and saw so sign of these pests, you need not worry.
I am attaching a link to a site that will give you more information on successfully growing Hibiscus.