Why Are Your Gardenia Leaves Yellow? Low Iron May Be the Culprit

This could be a sign of a few different problems. Here's what to look for to figure out what's going on with your plant.

Gardenias are one of the prima donnas of the plant world and they want everything just so, from the soil pH and drainage to the amount of water and fertilizer you give them. Luckily for them, their creamy white flowers have such a bewitching fragrance that they con us into meeting their persnickety needs, or at least trying very hard to keep them happy. So when some of the leaves on your gardenia start turning yellow, it can be worrisome. Let's walk through possible reasons why the leaves may be yellow, and look at a few easy solutions. Soon enough your fussy friend will be green and gorgeous again so it can produce more of those amazing, perfumed flowers that made you buy it in the first place.

gardenia flowers
hachiware/Getty Images

Gardenia Growing Basics

If you live in the warmer regions of the country (USDA Zones 8-11) you can grow gardenias outdoors where they're easier to maintain. Growing gardenias indoors during cold weather is where it gets tricky. The basic indoor gardenia needs are bright light, humidity, and regular watering. So try to put your plant in your sunniest window, set it on a saucer of rocks with water part way up the saucer to add humidity, and water it as soon as the top inch of soil feels dry.

Gardenia Leaves Turning Yellow

Naturally, some older leaves on gardenias may become yellow and drop off, particularly at the beginning of spring when the new leaves are on their way. This is normal so no need to start worrying. But if many older leaves are yellowing, your gardenia may be dying from root rot due to overwatering or poor soil drainage. Gently tip it out of its pot or if it's outdoors, lightly dig away a little soil at the base of the plant. If the roots you see are brown and squishy, the party's over. If you find white, firm roots, your plant still has a chance.

The most likely reason for yellow leaves on gardenias is low iron. But guess what? You don't need to add iron to solve the problem; you need to test the soil. Gardenias need acidic soil, which means soil with a pH between 5.0 and 6.5. This pH range makes iron in the soil available to gardenias. If the pH of your soil is outside those numbers, you can adjust it by adding an acidic fertilizer. Once your gardenia leaves are green again, use the fertilizer twice a month from early spring to late summer.

Because of their exacting care requirements, gardenias are among the trickier houseplants to grow and can be challenging as outdoor shrubs, too. Knowing what they require to look their best, and correctly diagnosing any problems that do crop up will help you enjoy your plant for many years to come.

Was this page helpful?
Related Articles