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5 Reasons Behind Gardenia Plant Leaves Turning Yellow

As a natural phenomenon, it is common for the aging leaves of Gardenia plants to fade and wilt. But as an evergreen plant, the leaves of Gardenia plants turning yellow may indicate more than aging.

Generally, leaves of Gardenia plants turning yellow may indicate watering issues, improper drainage, inadequate lighting, nutrient deficiency, and pest and disease infestation. You can fix the problem by balancing the watering schedule, fertilizer application, timely feeding, and regularly checking for pest invasion.

Follow along to learn in detail about the yellowing issues in Gardenia and their solutions.

Why Are My Gardenia Plant Leaves Turning Yellow? (Causes & Fixes)

The Gardenia plant, belonging to the coffee family Rubiaceae, is prized for its fragrance and beautiful creamy white flowers. 

However, failing to maintain the plant’s good health causes the yellowing of leaves which deters away the plant’s aesthetic and benefits it holds.

While aging could be a reason for the older leaves turning pale, inspecting the main cause is essential.

1. Watering Issues 

Gardenia are a little finicky when it comes to their watering habit. 

Usually, in zone 8 to 11, Gardenia does well with weekly watering. But anything severely off track from a normal watering regime, like over or under-watering, hinders the growth of the plant, its blooming, foliage growth, and color.

When you overwhelm the plant with more water than an inch or two, the pore space in the soil fills up.

This causes the root to suffocate and reduces the plant’s vigor. The leaves will be deprived of oxygen and nutrients and start browning and yellowing.

Likewise, the underwater Gardenias may exhibit slower growth and limited to no flowering. 

Further, due to inadequate water availability, the leaves become dry and brittle, followed by yellowing. Ultimately the leaves drop off. 

How to Fix?

  • In case of overwatering, immediately remove the plants from the pot and let them dry.
  • Carefully inspect for root rot and trim off any mushy or rotten roots.
  • Repot the plant in a terracotta pot with a few drainage holes and fresh, well-draining potting mix.
  • Monitor the soil moisture levels and water the plant when the top inch of the soil feels slightly dry. Avoid letting the soil become overly dry.
  • For extremely underwater plants, opt for the bottom watering method but remember to allow the drainage of excess. 

2. Improper Drainage

Gardenia plants thrive in well-draining, acidic soil as the plants are sensitive to waterlogging.

The compact soil failing to exert excess water suffocates the roots and inhibits the roots from uptaking oxygen and nutrients the plant requires. As a result, the deprived plants start wilting, leading to leaf chlorosis (yellowing) and stunted growth.

Moreover, if the condition persists for longer, the plant becomes prone to disease and pests, and you may lose the plant. 

Gardenia plant in a pot started turning yellow.
Yellowing starts from the bottom leaves and gradually moves up.

How to Fix?

  • Add coarse materials like perlite and sand to the compact soil to increase soil porosity and improve drainage.
  • Use a well-draining potting mix to plant the Gardenia instead of clay that will harden over time.
  • Adjust the watering frequency and amount to prevent waterlogging in your plant.
  • Avoid watering the plant from a height or with excessive force to minimize the chance of soil compaction. Use a watering can to minimize the potential impact.
  • Consider repotting the plant in a slightly bigger pot having enough drain holes. Make some if it lacks any.

Note: Make sure to keep you Gardenia at a distance from your pets as they content chemical having toxic effect to the pets. 

3. Improper Lighting

Gardenia plants love good sunlight but require partial shade to produce tubular white blooms.

Generally, Gardenia has no complaints about 6-8 hours of morning sunlight and indirect light during the hottest part of the day. 

However, harsh daylight burns the plant’s foliage turning them dry, crisp, and discolored.

Similarly, too little light hinders a plant’s photosynthesis by depleting the chlorophyll content in the leaves. Eventually, constant light stress cause the plant to fade and turn yellow. 

How to Fix?

  • Identify whether your plant is light deprived or saturated.
  • Move the plants 2 to 3 feet away from the window that receives direct light incidence. 
  • Use a sheer curtain to protect the plants against sunburn and foliar damage from scorching sunlight during summer. 
  • Make sure to rotate your potted plants now and then for equal light distribution throughout.
  • Consider moving the plant indoors under artificial grow light if winter drops below 20°F.

4. Nutrient Deficiency

Among all the other factors for the leaves of Gardenia plants turning yellow, detecting nutrient deficiency might be confusing.

Mostly, magnesium and iron deficiency in Gardenia leads to the yellowing of the leaves. But the symptom pattern differs from each other. 

You’ll know your plants are short of iron as the tips of the younger leaves fade away, but the base of branches and leaf bases remain green. 

On the contrary, the leaves of magnesium-deficient plants start yellowing from the base branch while the tips remain green. 

How to Fix?

  • Adjust the soil pH between 5 and 6 to ensure nutrient availability for the Gardenia.
  • For magnesium deficit plants, dilute two tablespoons of Epsom salt per gallon of water and mist it on the plant once a month. You may cut the amount to half and use it more frequently (every two weeks).
  • Use liquid chelate at the base of the iron-deficient plant and water them thoroughly.
  • If you overdo the fertilizer application, flush the excess under running water 4-5 times.

5. Pests and diseases

Apart from improper growing conditions, pests and diseases might be taking a toll on your Gardenia plant’s health.

Since Gardenia demands high humidity to thrive, excess moisture in air and soil invites diseases like powdery mildew and fungus that primarily affects young leaves and shoot.

Deformed leaves and buds with leaves losing their dark green color are the primary symptoms.

A spider mite on a Gradenia Leaves.
The pests, like Spider mites, nibble on the leaves as well.

While pests like whiteflies, Japanese wax scales, aphids, and spider mites sip the sap from the plants leaving behind blotched yellow patches on the leaves.

How to Fix?

  • Isolate the diseased or pest-infested plant from the healthy ones to prevent disease spread.
  • Prune the affected leaves, stem, and flower and dispose of them away from the plant and other vegetation.
  • Use high-pressure water to remove or wash away the pests’ eggs and larvae from the plant. 
  • You may apply horticultural oils like neem oil or fungicide against powdery mildew and pest like aphids.
  • Introduce beneficial interests like Ladybugs that would feed on the harmful pest helping to keep a check on their spread.
  • Ensure proper air circulation around your plant prevents high humidity from favoring pests and disease growth. 

From Editorial Team 

Regular Pruning and Deadheading!

Maintain the healthier leaves in Gardenia by pruning them in the summer months just after the last flower blooms.

Also, deadhead the spent flower to redirect the plant’s energy into overall growth and more flower blooms.