7 Reasons for Gardenia Yellow Leaves [Troubleshooting Guide]

People love gardenia for its white, creamy bloom and sweet fragrance. But the dark green leaves enhance the overall beauty of the plant. Most importantly, the green leaves directly involve the production of long-lasting flowers.

But if you notice your gardenia leaves are turning yellow, then it is high time to take care of your gardenias to save them. Otherwise, your plant will die or produce a poor set of blooms.

Now the question; why gardenia leaves turn yellow?

Yellow leaves on the gardenia plant may be caused by nutritional deficiency, over and under watering, imbalance of soil pH, lack of sunlight, Diseases, and Insects.

So, before taking any actions to fix the gardenia yellow leaves, you must know what exactly happens to the gardenia. Here I have discussed every possible reason for this problem with effective control measures.

Gardenia Leaves Turning Yellow & Dropping Off- Solutions

Botanically, The process of yellowing leaves is called chlorosis. In a simple word, chlorosis happens when the leaves don’t contain enough chlorophyll and you know chlorophyll is important for photosynthesis to produce energy for plants thriving and blooming.

Remember, the already yellowed leaves never turn green. So, before taking any action, always remove the yellow leaves first.

So, let’s see what step we should take to protect the gardenia plant from yellowing leaves-

1.Imbalance of Soil pH

Gardenias are acid-loving plants. They need acidic soil for uptaking the required nutrients. Generally, they grow well in soil pH between 5.0 to 6.5.

So, if the soil pH is higher than 7 then the gardenias can’t absorb some required nutrients like nitrogen, magnesium, iron, zinc, etc.

Solution

Check the soil pH with a digital soil pH meter(Our pick: Atree Soil pH Meter). If the pH remains in the optimum range, then soil pH is not responsible for yellow leaves on gardenia.

But if the pH of the soil is higher than 6.5, then you should acidify the soil. To do that, add some soil acidifier (our pick: Jobe’s Organics Soil Acidifier) to decrease the soil pH.

Also, you can also prepare a homemade solution to acidify the soil pH. Here is the DIY procedure for you-

#Vinegar

  1. Mix 5 tablespoons of vinegar into 1 liter of water.
  2. Pour the solution around the base of the gardenia plant once per month.

#Coffee Grounds

  1. Sprinkle 1 cup of coffee grounds around the gardenia plants.
  2. Mix into the surface soil and water the plant.

Note: Coffee grounds are highly acidic in nature. It helps the soil to reduce pH and also provide nitrogen to the plant.

2.Nutritional Deficiency

Lack of the required nutrients in the soil also can be the reason for yellow leaves on gardenias. Lack of nitrogen, magnesium, iron, and manganese can turn the leaves yellow. But magnesium and iron deficiencies are the most common problems for yellowing leaves.

Magnesium Deficiency in Gardenia Soil

Interveinal chlorosis is the identifying symptoms of magnesium deficiency. The lower or older leaves turn yellow first between the leaf veins and the tips of the leaves remain green.

Solution

  1. Mix 1 tablespoon of Epsom salt(our pick: Monterey LG7220 Epsom Salt for Plants) into a gallon of water.
  2. Pour the water on the base of the gardenia plant.

Note: Epsom salt is the natural source of magnesium. So, it can provide magnesium to your plant. Also, you can apply magnesium fertilizer.

Iron Deficiency in Gardenia Soil

Iron deficiency symptoms first appear in the younger leaves of the plant. So, you will notice the yellow upper leaves with green veins.

Solution

Apply 1/4 teaspoon of iron chelate or iron sulfate on your gardenia bushes and meet the iron demand of your plant. Here is the recommended chelated iron for your plants-

  1. Monterey NLG7122 Dr. Iron
  2. Espoma IT5 Organic Iron-Tone Plant Food

Nitrogen Deficiency of Gardenia plants

Because of nitrogen deficiency, the leaves and vein of gardenia turn yellow and it occurs in the older leaves first.

Solution

Feed the nitrogenous fertilizer by following the label direction of the fertilizer. Also, have some natural nitrogen fertilizer that you can apply such as coffee grounds, animal manure, etc.

#Coffee grounds

  1. Sprinkle 1 cup of coffee grounds on the gardenia plants.
  2. Mix it with 1 to 3 inches of surface soil gently.
  3. Water the gardenia to start feeding.

Quick Tips: If it seems complicated to understand what are the exact nutrients the plant needs. Then you may apply good gardenia acid fertilizer that contains nitrogen, magnesium, iron, and some other macro and micronutrients. Our pick-

3.Poor Drainage Facilities

Do your Indoor gardenia plant leaves turn yellow? Then probably the leaves are yellowing for poor drainage. Generally, the drainage problem mostly occurs in potted plants rather than in-ground gardenia.

If the gardenia soil has poor drainage, the extra soil can rot the root and because of the root rot, the plant can’t take the required nutrients. As a result, the leaves of the plant are getting yellow.

Solution

Create a drainage hole if the pot doesn’t have and repot the plant with good potting soil that has good drainage. Our pick-

  1. Espoma AP4 Organic Potting Mix
  2. Miracle-Gro Moisture Control Potting Mix

You can also add some perlite (our pick: Espoma Organic Perlite), sand, or vermiculite with your existing soil to improve drainage.

4.Over-Watering and Under-watering

Yellow leaves on gardenia can be caused by both over-watering and under-watering. So, it will be tricky to find out the leaves are turning yellow because of over-watering or under-watering.

To understand-

Insert the finger or a stick into the soil of the gardenia plant. If you feel dry, the leaves may turn yellow for underwatering. If you feel the soil wet, then probably it has happened for over-watering.

The best idea to know the moisture level of the plant, you should use a moisture meter(our pick:)

Solution

To avoid improper watering to the gardenia bushes, you should know when and how much water applies on the gardenia plants.

Though the weather and soil water retaining capacities can tell the exact watering schedule of gardenia, you should apply 1 inch water per week to your plants. The schedule will be changed. Just remember, the soil must be moist but not over-saturated.

Also, the good potting mix and soil condition can help the plant to protect from improper watering as well as yellow leaves.

5.Lack of Sunlight

Gardenia plants love to grow in the morning sun. They need 6-8 hours of direct sunlight to thrive and grow well. If they don’t get sufficient sunlight and grow in cool weather, photosynthesis won’t take place. As a result, you will get the gardenia that has yellow leaves.

Solution

Change the growing place of your gardenia plants, where they get a minimum of 6 hours of sunlight. Never park your car in front of the gardenia plants for a longer period of time. Also, prune the plants to increase light and air circulation.

6.Diseases

Different types of diseases can be the reason for yellow leaves. Sooty mold, Leaf spots are the most fungal diseases that can turn the green leaves into yellow. Both are the fungal diseases that cause gardenia leaves turning yellow and black or brown.

Solution

Prune the gardenia bushes and increase air circulation. Air circulation can reduce the chance of fungus development. Lastly, apply a fungicide(our pick: Southern Ag – Liquid Copper Fungicide) to control fungal diseases.

Also, you can prepare fungicide at home to protect your gardenias from fungal diseases-

#Vinegar

  1. Mix 1 cup vinegar into a quart of water.
  2. Spray the solution on the foliage until the leaves become wet completely.

The vinegar solution also helps the soil to reduce pH and create an acidic environment for gardenias.

#Ammonia

  1. Mix 2 cups ammonia into 2 cups water(50:50)
  2. Pour the solution into a sprayer.
  3. Spray the ammonia solution on the foliage of gardenias.

7.Insects

Insects contain toxins. When they try to suck the plant sap, the toxin enters the plant cells. As a result, the leaves show tiny black spots and the leaves become yellow gradually.

Gardenia can be affected by mealybugs, ants, caterpillars, aphids, mites but the most affected gardenia leaf insect is mealybugs.

Observe the gardenia bushes, if you notice any movement of the insects, yellowing leaves may happen for insects. Inspect the lower surface of the leaves, most of the insects hang on there.

Solution

Spray insecticide to get rid of insects from gardenia plants. Neem oil, Insecticidal soap or other organic and chemical insecticide can be applied.

Here is the recommended neem oil, insecticidal soap, and insecticide. You may pick any of these for your gardenia plants-

  1. Safer 5180-6 Neem Oil Ready-to-Use
  2. Natria 706230A Insecticidal Soap
  3. Bonide (BND857) – Pyrethrin Garden Insect Spray Mix

You can also prepare insecticide at home. Here is the recipe for you-

#Insecticidal Soap

  1. Mix 1 cups of liquid soap into a gallon of water.
  2. Spray the solution on the gardenia plant.

Want to get the more effective insecticidal soap recipe? Check our article- Homemade insecticidal soap

#Garlic Spray

  1. Chop into pieces 15-20 cloves of garlic.
  2. Mix 1 or 2 liters of water with the chopped garlic.
  3. Boil the water and stir while boiling.
  4. Wait for 20 minutes with a lid on the pot.
  5. Let the solution cool and spray on the gardenia plants.

To learn more about garlic spray-How to make garlic spray for the garden to get rid of insects

How to Prevent Gardenia Yellow Leaves?

Only the proper care can prevent gardenia yellow leaves. Here are some preventive tips for you-

  1. Plant your gardenia well-drained pot and potting soil.
  2. Choose the right growing site where the plant gets enough sunlight.
  3. Keep the soil acidic.
  4. Stagnant water is harmful to plants. So, apply less water more frequently.
  5. Apply the nutrient-enriched acid fertilizer for gardenia by following the label directions.
  6. Apply neem oil or any other preventive insecticide and fungicide.

Final Words

I hope you got to know what you should do to protect the gardenia yellow leaves. So, don’t waste your time, remove the yellow leaves, and take the controlling measure and revive the plants.

I wish, your gardenia will become bushy with lots of dark green leaves and healthy blooms.

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