Tropical Hibiscus Flowers
hawaiian hibiscus
(Image credit: danielvfung)

Tropical hibiscus fertilizing is important to keeping them healthy and blooming beautifully, but tropical hibiscus plant owners may wonder what kind of hibiscus fertilizer they should be using and when they should be fertilizing hibiscus. Let's look at what's necessary to be fertilizing hibiscus trees properly.

What Hibiscus Fertilizer to Use

The best hibiscus tree fertilizers can be either slow release or water soluble. With either, you will want to fertilize your hibiscus with a balanced fertilizer. This will be a fertilizer that has all the same numbers. So, for example, a 20-20-20 or 10-10-10 fertilizer would be balanced fertilizer. If you will be using a water soluble fertilizer, use it at half strength to avoid over fertilizing the hibiscus tree. 

Over fertilizing hibiscus plants result in burning the roots or providing too much fertilizer, which will cause in fewer or no blooms or even yellow, dropping leaves.

When to Fertilize Hibiscus

Hibiscus do best when given hibiscus fertilizer frequently but lightly. Doing this helps to make sure that the hibiscus tree will grow well and bloom frequently without over fertilizing. If you are using a slow release fertilizer, you will want to fertilize 4 times a year. These times are:

  • Early spring
  • After the hibiscus tree finishes its first round of blooming
  • Mid summer
  • Early winter

If you are using water soluble fertilizer, you can fertilizer with a weak solution once every 2 weeks in spring and summer and once every four weeks in fall and winter.

Tips for Fertilizing Hibiscus

Hibiscus fertilizing is pretty basic, but there are a few tips that can help make it easier. Whether your hibiscus grows in the ground or in a pot, make sure that you put fertilizer out to the edges of the hibiscus tree's canopy. 

Many people make the mistake of fertilizing just at the base of the trunk and the food does not have a chance to reach the full root system, which extends to the edge of the canopy. If you find that you have over fertilized your hibiscus and it is blooming less, or not at all, add phosphorus to the soil to help bring the hibiscus blooms back.

Heather Rhoades
Founder of Gardening Know How

Heather Rhoades founded Gardening Know How in 2007. She holds degrees from Cleveland State University and Northern Kentucky University. She is an avid gardener with a passion for community, and is a recipient of the Master Gardeners of Ohio Lifetime Achievement Award.