Skip to main content
Master Gardeners

Keeping Gardenias Healthy

May is a good month to take a close look at one of our favorite plants, the gardenia. These shrubs are evergreen, and like other evergreens, they do lose and replace leaves as time goes by. Even fifty-year-old gardenias grow shiny, brand-new, dark green leaves in the spring.

Before the old leaves drop, they turn yellow – that’s normal. What is not normal, however is yellow leaves all over the plant, or the majority of leaves being yellow, or yellow veins on green leaves (or vice versa). That may be a sign of a micronutrient deficiency.


Gardenia with yellowing leaves. Photo credit: Celia Beamish, UF/IFAS Extension

The problem is that plants need minerals to be dissolved in water to absorb them. And if the soil pH is wrong, the minerals won’t dissolve. So May is a good time for a soil test. Once you know the pH is correct, you can apply slow-release fertilizer with micronutrients.

While you’re checking your gardenia’s soil, why not take a magnifying glass and check new growth for tiny creatures called thrips, scale, or mites? All of them eat by sucking juice from a plant, and they all like gardenias, especially in warm weather. Thrips are a common cause of bud drop.

For more information on gardenias, please look online at, at, call the Polk County Master Gardeners at 863-519-1041, or drop us a note at

This month’s Florida-Friendly™ reminder: Find out what kind of conditions your plant likes BEFORE planting it. Right plant, right place, is the right way to successful gardening in central Florida.


This blog post was written by Master Gardener Celia Beamish under supervision of the Master Gardener Coordinator and Residential Horticulture Agent Anne Yasalonis.

For more information, contact UF/IFAS Extension Polk County at (863) 519-1041 or visit us online at  The Plant Clinic is open Monday-Friday, 9:00 am-4:00 pm to answer your gardening and landscaping questions. Visit us in person, give us a call, or email us at

The Florida Master Gardener Program is a volunteer-driven program that benefits UF/IFAS Extension and the citizens of Florida.  The program  extends the vision of the University of Florida/Institute of Food and Agricultural Sciences, all the while protecting and sustaining natural resources and environmental systems, enhancing the development of human resources, and improving the quality of human life through the development of knowledge in agricultural, human and natural resources and making that knowledge accessible.

An Equal Opportunity Institution.

4 Comments on “Keeping Gardenias Healthy

  1. Hello Anne
    May I ask, how long will it take to wait for the pH test to finish. Thank you