Yellow Leaves on Gardenia: Causes | Treatments | Prevention Tips

Yellow leaves on gardenia are often a sign of chlorosis, a common condition occurring when a plant does not have enough chlorophyll.

Gardenia [gar-DEEN-ya] is a genus of plants belonging to the Rubiaceae (coffee) family. 

Most species of gardenia are native to subtropical and tropical regions throughout Asia, Africa, and the Pacific islands. 

white blooms of the intoxicatingly fragrant Gardenia plant

Some of the most popular varieties of gardenias are evergreen shrubs producing clusters of flowers, such as Gardenia Grandiflora.

Gardeners frequently encounter yellow leaves when cultivating gardenias. 

The following information covers the recommended methods for treating and preventing the issue.

What Damage Does Yellow Leaves on Gardenia Plants Cause?

When gardenia leaves turn to yellow it is a symptom of a variety of different plant problems. 

No matter the initial reason for the problem, the yellowing is typically due to a lack of chlorophyll. 

When plants do not receive enough nutrients from the soil, the leaves cannot achieve their typical bright green color. 

This problem is known as chlorosis.

Some of the most common causes of chlorosis in species of gardenia plants include:

  • pH imbalances
  • Magnesium deficiencies
  • Iron deficiencies
  • Poor drainage
  • Too much watering

Without treatment, the plant may not survive. 

The initial cause of the yellow leaves continues to prevent the gardenias from receiving enough nutrients. 

After the leaves turn yellow, they may start to wilt, eventually falling from the stems. 

This is a common problem, and several solutions exist for dealing with it. 

However, if the plant continues to yellow and wilt, the best option is often to start over with a new plant.

How to Treat Gardenia Leaves Turning Yellow

When signs yellowing leaves first show, check the drainage and watering schedule. 

Overwatering is the most common cause of chlorosis in plants.

Gardenias require moist soil. 

However, oversaturation deprives the plant of proper nutrition, resulting in the yellow leaves. 

To improve drainage, add compost, or other organic material. 

Only water the soil when the top two to three inches are dry. 

If these steps solve the issue, the leaves should eventually regain their original hue. 

The leaves should be a bright green color.

If improving the drainage or limiting the watering doesn’t solve the issue, it’s time to look at the other potential causes of chlorosis.

Most nutrient issues stem from a pH imbalance. 

Gardenias require a pH level between 5.0 and 6.5. 

Maintaining proper pH levels allows the plant to absorb more minerals from the soil, helping to prevent deficiencies which often lead to chlorosis. 

If the soil is too acidic or alkaline, it starves. 

Testing kits are available to determine the pH level. 

It’s also possible to determine whether the levels are too high or too low based on the appearance of the yellow leaves.

Using Liquid Nutrients and Fertilizer

Adding a liquid plant fertilizer to the soil helps deliver more nutrients to the plant, but doesn’t completely solve the issue if a pH imbalance remains.

Liquid nutrients applied directly to the plant also provide a temporary fix, but don’t permanently resolve the problem. 

Instead of applying liquid fertilizer to the plant or soil, use limestone or sulfur, based on the appearance of the leaves.

Treating a Magnesium Deficiency

If the pH level is below 5.0, the tips of the leaves may remain green. 

A dark green triangle may also appear near the base of the leaf. 

These signs indicate the plant is suffering from a magnesium deficiency caused by low pH levels.

Add limestone to the soil to help increase pH levels. 

Epsom salts and magnesium salt also increase the alkalinity of the soil.

Treating an Iron Deficiency 

If the tips are yellow and the base of the leaves remain green, the plant is suffering from the opposite problem. 

Instead of acidic soil, it has alkaline soil with a pH level above 6.5.

With elevated pH levels, the plant cannot get enough iron, resulting in an iron deficiency. 

To correct the issue, add sulfur, which lowers pH levels due to its acidic content.

When adding compounds to correct pH imbalances, avoid excessive application. 

Over applying salt or sulfur may impact the overall quality of the soil.

How to Prevent Yellow Leaves on Gardenias

The best way to prevent yellow leaves is to ensure the gardenias receive optimal growing conditions and nutrients.

Grow gardenias in rich soil with good drainage. 

Remember to add organic matter if the soil requires faster drainage. 

Check the pH level of the soil, aiming for a reading between 5.0 and 6.5. 

Remember to add limestone to raise the pH level and sulfur to decrease it. 

Even when following the best practices for cultivating gardenias, yellow leaves may still appear. 

Even experienced gardeners occasionally lose gardenias to chlorosis. 

If one gardenia succumbs to the problem, grow a new one from seed or division.